Bacterial cellulose production by Acetobacter xylinum ATCC 23767 using tobacco waste extract as culture medium

Bio-synthesis of bacterial cellulose from ramie textile waste for high-efficiency Cu(II) adsorption

The current study aims at the high-value utilization of ramie textile waste and explores a bio-synthetic pathway to convert waste ramie fibers into bacterial cellulose (BC). Ramie fibers were treated with commercial cellulase (C2730) and the hydrolysate was used as a base medium (RFH) for BC synthesis by fermentation. The enzymatic hydrolysis parameters were optimized by response surface methodology, yielding an optimal temperature of 40 °C, 64 h, and an enzyme dosage of 5.7%. Under these optimized conditions, the resultant yield of reducing sugars was 31.24 ± 0.37 g/L. And then the Novacetimonas hansenii HX1 strain isolated from kombucha was used for fermentation production of BC. The study found that adding yeast extract into RFH can significantly increase BC production, and 7.2 g/L BC can be produced within 7 days. The physical and chemical properties of BC were then analyzed, including Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Thermogravimetric analysis (TGA), confirming its type Iα cellulose structure and good thermal stability. In particular, BC shows efficient adsorption capacity for Cu(II) ions in aqueous solution, with the highest adsorption efficiency reaching 95.62%. This research not only provides a new way to recycle textile waste, but also lays the foundation for the application of BC in the field of environmental remediation.

Production of bacterial cellulose with high active components loading capacity for skin wound repair

Scutellaria baicalensis extracts (SBACs), a herb that contains a variety of bioactive flavonoids like baicalein and baicalin, which impart antibacterial, antioxidant, and other biological activities, were used to create bacterial cellulose (BC) with a high components-loading capacity in-situ. Higher S-L ratios raised the quantities of the active ingredients (baicalin and baicalein), enhancing antibacterial and antioxidant activities. Considering both components-loading efficiency (322 mg/g of baicalin and 8.79 mg/g of baicalein) and production viability, an S-L ratio of 1:20 was determined as the optimal for preparing BC/SBACs membranes. These membranes exhibited superior mechanical strength and thermal stability compared to pure BC. Furthermore, when compared to membranes made via physical adsorption, the in-situ produced BC/SBACs exhibited a higher capacity for loading components and a more effective release of those components. A three-dimensional network structure was discovered using morphological analysis, which facilitated the integration of active ingredients. In vitro biocompatibility tests showed that BC/SBACs hydrogel was safe, exhibiting no hemolysis and low cytotoxicity. In vivo experiments on a full-thickness skin defect model in mice demonstrated a significantly higher wound-healing rate. The study highlights the potential of BC to improve clinical treatment outcomes by providing an easy way to combine it with traditional Chinese medicine.

Comparison of bacterial cellulose production by various biomass wastes as culture media

Bacterial cellulose (BC) has been widely used in various fields because of its excellent physical and chemical characteristics. However, the high production cost limits its applications. This study focused on the investigation of culture media prepared from three kinds of biomass wastes including vinegar residue (VR), paper mulberry (PM), and seagrass (SG), and their potential for BC production using kombucha was evaluated. VR, PM, and SG were hydrolyzed using acetic acid and enzyme treatment to obtain reducing sugars in concentrations of 14.78 g/L, 11.73 g/L, and 12.23 g/L, respectively, under optimized thermohydrolytic and enzymatic hydrolysis conditions. All biomass wastes applied in this study supported BC production, among which BC yields from VR (5.36 g/L) and PM (4.27 g/L) media were higher than Hestrin-Schramm (HS) (1.13 g/L) medium. In comparison, the SG (0.70 g/L) medium was lower. The BC samples were evaluated using SEM, FTIR, XRD, and TG analysis. Average fiber diameters and crystallinities of BC obtained from VR (60 nm, 77.39 %) and PM (58 nm, 67.54 %) media were higher than those obtained from HS (38 nm, 66.88 %) and SG (35 nm, 62.81 %) media. Iα content of BC from the three biomass waste media ranged from 0.47 to 0.48 and was higher than from the HS (0.43) medium. The thermal stability of BC from the SG medium was higher than that of other media. The current study demonstrated that biomass wastes especially VR and PM are promising carbon sources for sustainable production of BC.

A Green Method for Bacterial Cellulose Electrospinning Using 1-Butyl-3-Methylimidazolium Acetate and γ-Valerolactone

Bacterial cellulose (BC) is a highly pure and crystalline cellulose produced via bacterial fermentation. However, due to its chemical structure made of strong hydrogen bonds and its high molecular weight, BC can neither be melted nor dissolved by common solvents. Therefore, processing BC implies the use of very strong, often toxic and dangerous chemicals. In this study, we proved a green method to produce electrospun BC fibers by testing different ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium acetate (BmimAc), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimTFSI) and 1-ethyl-3-methylimidazolium dicyanamide (EmimDCA), either individually or as binary mixtures. Moreover, γ-valerolactone (GVL) was tested as a co-solvent derived from renewable sources to replace dimethyl sulfoxide (DMSO), aimed at making the viscosity of the cellulose solutions suitable for electrospinning. A BmimAc and BmimAc/EmimTFSI (1:1 w/w) mixture could dissolve BC up to 3 w%. GVL was successfully applied in combination with BmimAc as an alternative to DMSO. By optimizing the electrospinning parameters, meshes of continuous BC fibers, with average diameters ~0.5 μm, were produced, showing well-defined pore structures and higher water absorption capacity than pristine BC. The results demonstrated that BC could be dissolved and electrospun via a BmimAc/GVL solvent system, obtaining ultrafine fibers with defined morphology, thus suggesting possible greener methods for cellulose processing.

Advances in biomedical applications of bacterial cellulose: from synthesis mechanisms to commercial innovations

Bacterial cellulose (BC) has various unique properties, such as sustainability and biocompatibility, which make it a "rising star" in biomedical applications. This comprehensive review delves into the intricacies of BC production and elucidates the pivotal role of rosette terminal complexes in the synthesis of BC. Moreover, it explores the diverse range of in-situ and ex-situ modifications, such as coating, genetic modification, and esterification, that can enhance its performance in biomedical applications, notably in tissue engineering, drug delivery and wound healing applications Beginning with an in-depth examination of BC synthesis mechanisms, this review sheds light on the fundamental processes underlying its unique structure and properties and subsequently delves into the vast landscape of modification strategies, encompassing techniques such as chemical functionalization, surface patterning, and composite formation. Of particular significance are the insights provided into commercial products derived from BC, which offers a comprehensive overview of their features and applications, followed by several recent case studies. By consolidating knowledge from the basic principles of BC synthesis to cutting-edge advancements in the field, this review illuminates the transformative impact of BC on the landscape of health and medical breakthroughs, paving the way for future advancements in biomedicine.

Novel Approaches in Production and Application of Bacterial Cellulose in Food Industries

Bacterial cellulose (BC) is a polymer produced by specific species of bacteria, most often by the species Komagataeibacter xylinus and Gluconacetobacter xylinus. BC may be distinguished from other types of cellulose by its origin. It is a kind of cellulose that is highly pure and robust, which is made up of long chains of glucose units that create a 3D network. The production of BC takes place via fermentation. During this process, the bacteria utilize sugar and produce cellulose as a byproduct. BC has been extensively researched for its potential use in the medical industry, food industry, and many other fields. Application includes development of an artificial skin for wound dressing because of its remarkable inter- and intramolecular hydrogen bonding and thermal and mechanical strength. BC has a large potential to be used in the food industry, where it can be combined with other polysaccharides to be used in food products as additives, edible film/coating, or active food packaging material to prolong the shelf life of the product and reduce the rate of chemical reactions and microbial growth in food products.

Improved bacterial cellulose production by Acetobacter oryzoeni MGC-N8819 in tobacco waste extract coupled with nicotine removal by Pseudomonas sp. JY-Q/5∆

As the substrate, tobacco waste extract (TWE) can produce bacterial cellulose (BC), a biobased material. However, nicotine inhibits BC production (adding 0.8 g/L nicotine to the HS medium had a negative effect on BC synthesis) and needs to be removed. In this study, BC production by Acetobacter oryzoeni MGC-N8819 was carried out in four dilutions (5 %, 10 %, 15 %, and 20 %) of TWE. 15 % TWE without nicotine removal resulting in a 3.27 g/L BC production. Considering the inhibitor effect of nicotine on BC synthesis. Pseudomonas sp. JY-Q/5∆, an efficient nicotine-degrading mutant strain without the ability of glucose consumption, was statically co-cultured with MGCN8819, and the BC production was increased to 4.61 g/L after 7 days of cultivation. To eliminate the limitation of insufficient oxygen supply, BC films were harvested on day 7 and cultured for an additional 5 days resulting in a 6.00 g/L final BC production. Remarkably, the co-culture of MGC-N8819 and JY-Q/5∆ improved BC properties in terms of fiber diameter (28 nm), mechanical properties (tensile strength to 67 MPa and elongation at break to 23 %), and thermal stability (the maximum decomposition temperature was 600 °C). This study suggests a valuable strategy for improving BC production using agricultural waste.

Sustainable Bacterial Cellulose Production Using Low-Cost Fruit Wastewater Feedstocks

Bacterial cellulose (BC) is a versatile biopolymer prized for its remarkable water absorption, nanoscale fiber architecture, mechanical robustness, and biocompatibility, making it suitable for diverse applications. Despite its potential, the high cost of conventional fermentation media limits BC's scalability and wider commercial use. This study investigates an economical solution by utilizing fractions from fruit processing wastewater, refined through sequential membrane fractionation, as a supplement to commercial HS medium for BC production. BC films were thoroughly characterized using Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and assessments of mechanical properties and water holding capacity (WHC). FTIR confirmed the BC structure, while TEM validated its nanofibrillar 3D network. XRD analysis revealed a slight increasing trend in crystallinity with the addition of wastewater fractions, and DSC revealed a slight increase in thermal stability for F#6. Adding these fractions notably improved the BC films' tensile strength, Young's modulus, and WHC. Overall, the results underscore that fruit processing wastewater fractions can serve as a cost-efficient, eco-friendly alternative to traditional fermentation media. This approach supports circular economy principles by lowering reliance on intensive wastewater treatments, promoting waste valorization, and advancing sustainable production methods for high-value biopolymers.

Effect of microbial community on the formation of flavor components in cigar tobacco leaves during air-curing

BACKGROUND

The air-curing process of cigar tobacco leaves is typically conducted in an open environment, involving the participation of various microorganisms. However, the effect of microbial communities during air-curing process on the formation of flavor components remains unclear. Therefore, this study aims to reveal the dynamics of flavor components and microbial community changes, and explore the potential role of microbial communities in flavor formation during the cigar tobacco air-curing process.

RESULTS

High-throughput sequencing analysis showed that Pantoea, Sphingomonas and Pseudomonas were the dominant bacterial genera during air-curing process, while Aspergillus was the dominant fungal genus. Subsequently, volatile flavor analysis shows that alkaloids were the most important volatile compounds in cigar leaves, followed by esters, alcohols and aldehydes. Furthermore, 38 characteristic volatile flavor compounds at different periods of air-curing were identified based on PLS-DA in different periods of air-curing. The correlation analysis between microorganisms and flavor components showed that Pantoea and Staphylococcus might promote the flavor formation from browning to post-air-curing and were positively correlated with specific flavor components like phenylacetaldehyde and acetophenone. Phoma, Mycosphaerella, Wallemia, and Cladosporium were identified as key fungal genera influencing flavor formation, as they showed positive correlations with multiple flavor components. These information enrich our understanding of the flavor formation of cigar tobacco during air curing.

CONCLUSIONS

There is a complex correlation between the microbial community and the flavor components, which may have a great influence on the flavor formation during the air-curing process of cigar leaves. Bacterial communities have higher species diversity and richness during air-curing, and have more complex correlation characteristics with volatile flavor, which may play more roles in the flavor formation. This study revealed the potential role of microbial community on flavor formation in cigar tobacco air-curing process, and provided guidance for subsequent screening of specific functional microorganisms to improve and stabilize cigar tobacco flavor.

Insights into bacterial cellulose for adsorption and sustained-release mechanism of flavors

The stabilities and sustained-release properties of citral are significant for foods. Herein, bacterial cellulose (BC) was innovatively reported for adsorption and sustained-release of citral via gas-phase adsorption technique, and the adsorption mechanism was disclosed. BC was prepared from tobacco stem waste extract (TSWE), and better adsorption capacity (124.98 mg/g) was obtained through response surface optimization. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Flourier transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) were utilized to verify the successful adsorption. Thermo-gravimetry (TG) analysis showed that the release of citral was delayed. Temperature responsiveness indicated the release of citral was controlled by internal diffusion. Density functional theory (DFT) calculations indicated the interactions between BC and citral was mainly composed of van der Waals forces and hydrogen bonds. BC-Citral also exhibited excellent antibacterial capability. This work provided a new approach for constructing controlled-release materials of citral, which offered good application prospects in food industry.

Comparing diverse extraction methodologies to infer the performance of 1,8-cineole extraction from Eucalyptus cinerea: process optimization, kinetics, and interaction mechanisms

Eucalyptus oil is highly valued for its anti-inflammatory, antiviral, and antibacterial qualities. Research has shown that it is a powerful combatant against cancer cells, making it an extremely interesting area of research. For the first time, the present study proposes to extract 1,8-cineole from Eucalyptus cinerea leaves using different extraction methodologies, namely, hydro-distillation (HD), Soxhlet (SE), ultrasonication (UE), and microwave (ME) extraction techniques. In conventional extraction, HD yielded a maximum of 72.85% 1,8-cineole using a minimum solid-solvent ratio of 1 : 10 g mL-1 within 3 h compared to SE. The first-order kinetic equation was applied in the HD experimental dataset to understand the extraction mechanism. In modern extraction technology, ME achieved the highest yield of 1,8-cineole (95.62%) at the optimal solid-solvent ratio of 2 g mL-1, extraction time of 4.5 min, and irradiation power of 640 W using the response surface methodology (RSM). Furthermore, the kinetic analysis of UE was investigated using three different empirical models. The chemical components of the essential oil extracted using each extraction method were identified as oxygenated monoterpenes, sesquiterpenes, and oxygenated sesquiterpenes using gas chromatography. Following extraction using various techniques, the morphology of spent leaves lost its distinct texture, their oil glands were entirely distorted, and their vascular bundles could still be identified. It was observed that the hydrogen bond interaction between the solvent molecule and 1,8-cineole-like value-added components played a role in the extraction. Among the investigated techniques, the solvent-free ME method is the most environmentally acceptable method and could effectively extract essential oil from E. cinerea leaves.

YourTuber matters: Screening for potato variety for the synthesis of bacterial cellulose in its tuber juice

This study aimed to characterize potato varieties for producing potato juice media (PJM) that allow bacterial cellulose (BC) effective and cost-efficient production. The study used 12 edible and 10 starch potato varieties from an accredited company for breeding and seed production. In general, edible varieties produced a 73 % higher PJ yield. Favorable BC yields were obtained using five edible and two starch varieties. Notably, the average BC yields in PJM from three edible varieties (Altesse, Mazur, and Owacja) were above the average BC yield from Hestrin-Schramm (HS) medium (4.3, 4.1, and 3.9 g/L v. 3.69 g/L, respectively); these varieties had relatively high concentrations of glucose (3.3-4.2 g/L), fructose (3.0-4.2 g/L), and sucrose (2.9-4.2 g/L). It was also shown that the macro- and microstructure, crystallinity, and polymerization degree showed no significant differences between PJM-derived BC and HS-BC. As estimated, the cost of PJM required to produce 1 kg of BC is approximately EUR 60. In contrast, the cost of HS medium exceeds 1200 EUR. In conclusion, our research has proven that PJM can significantly reduce the costs (by over tenfold) of the medium for BC biosynthesis, ultimately lowering overall costs of producing this valuable biomaterial.

Citrate-buffered Yamanaka medium allows to produce high-yield bacterial nanocellulose in static culture using Komagataeibacter strains isolated from apple cider vinegar

Bacterial nanocellulose (BNC) is a sustainable, renewable, and eco-friendly nanomaterial, which has gained great attentions in both academic and industrial fields. Two bacterial nanocellulose-producing strains (CVV and CVN) were isolated from apple vinegar sources, presenting high 16S rRNA gene sequence similarities (96%-98%) with Komagataeibacter species. The biofilm was characterized by scanning electron microscopy (SEM), revealing the presence of rod-shaped bacteria intricately embedded in the polymeric matrix composed of nanofibers of bacterial nanocellulose. FTIR spectrum and XRD pattern additionally confirmed the characteristic chemical structure associated with this material. The yields and productivities achieved during 10 days of fermentation were compared with Komagataeibacter xylinus ATCC 53524, resulting in low levels of BNC production. However, a remarkable increase in the BNC yield was achieved for CVV (690% increase) and CVN (750% increase) strains at day 6 of the fermentation upon adding 22 mM citrate buffer into the medium. This effect is mainly attributed to the buffering capacity of the modified Yakamana medium, which allowed to maintain pH close to 4.0 until day 6, though in combination with additional factors including stimulation of the gluconeogenesis pathway and citrate assimilation as a carbon source. In addition, the productivities determined for both isolated strains (0.850 and 0.917 g L-1 d-1) compare favorably to previous works, supporting current efforts to improve fermentation performance in static cultures and the feasibility of scaling-up BNC production in these systems.

Three-Dimensional Metal-Organic Framework@Cellulose Skeleton-Reinforced Composite Polymer Electrolyte for All-Solid-State Lithium Metal Battery

High-safety and high-energy-density solid-state lithium metal batteries (SSLMBs) attract tremendous interest in both academia and industry. Especially, composite polymer electrolytes (CPEs) can overcome the limitations of single-component solid-state electrolytes. In this work, a strategy of combining a rigid functional skeleton with a soft polymer electrolyte to prepare reinforced CPEs was adopted. The in situ grown zeolitic imidazolate frameworks (ZIFs) with three-dimensional cellulose fiber skeleton (ZIF-67@CF) and succinonitrile (SN) plasticizer into poly(ethylene oxide) (PEO) together form ZIF-67@CF/PEO-SN CPEs. The addition of ZIF-67@CF and SN to PEO synergistically enhanced the physical and electrochemical properties of CPEs. Furthermore, the conduction mechanism of lithium-ion (Li+) in CPEs was studied using density functional theory. It is impressive that the ZIF-67@CF/PEO-SN CPEs at 30 °C exhibit a high ionic conductivity of 1.17 × 10-4 S cm-1, a competitive Li+ transference number of 0.40, a wide electrochemical window of 5.0 V, a notable tensile strength of 18.7 MPa, and superior lithium plating/stripping stability (>550 h at 0.1 mA cm2). Such favorable features endowed LiFePO4/(ZIF-67@CF/PEO-SN)/Li cell at 30 °C with a high discharging capacity (152.5 mA h g-1 at 0.2 C), a long cycling lifespan (>150 cycles with 99% capacity retention), and superior operating safety. This work provides insights and promotes the application of functionalized CPEs for SSLMBs.

Optimization of bacterial cellulose production by Komagataeibacter sucrofermentans in synthetic media and agrifood side streams supplemented with organic acids and vitamins

The effect of thiamine (TA), ascorbic acid (AA), citric acid, and gallic acid (GA) on bacterial cellulose (BC) production by Komagataeibacter sucrofermentans, in synthetic (Hestrin and Schramm, HS) and natural substrates (industrial raisins finishing side stream extract, FSSE; orange juice, OJ; green tea extract, GTE), was investigated. The Response Surface Methodology was found reliable for BC yield prediction and optimization. Higher yields were achieved in the FSSE substrates, especially those supplemented with AA, TA, and GA (up to 19.4 g BC/L). The yield in the non-fortified substrates was 1.1-5.4 and 11.6-15.7 g/L, in HS and FSSE, respectively. The best yield in the natural non-fortified substrate FSSE-OJ-GTE (50-20-30 %), was 5.9 g/L. The porosity, crystallinity, and antioxidant properties of the produced BC films were affected by both the substrate and the drying method (freeze- or oven-drying). The natural substrates and the process wastewaters can be further exploited towards added value and sustainability. Take Home Message Sentence: Raisin and citrus side-streams can be efficiently combined for bacterial cellulose production, enhanced by other vitamin- and phenolic-rich substrates such as green tea.

Preparation and characterization of bacterial cellulose synthesized by kombucha from vinegar residue

Bacterial cellulose (BC) has been widely applied in various fields due to its excellent physicochemical properties, but its high production cost remains a challenge. Herein, the present study aimed to utilize the hydrolysate of vinegar residue (VR) as the only medium to realize the cost-effective production of BC. The BC production was optimized by the single-factor test. The treatment of 6 % VR concentration with 3 % acid concentration at 100 °C for 1.5 h and 96 U/mL of cellulase for 4 h at 50 °C obtained a maximum reducing sugar concentration of about 32 g/L. Additionally, the VR hydrolysate treated with 3 % active carbon (AC) at 40 °C for 0.5 h achieved a total phenol removal ratio of 86 %. The yield of BC reached 2.1 g/L under the optimum conditions, which was twice compared to the standard medium. The produced BC was characterized by SEM, FT-IR, XRD, and TGA analyses, and the results indicated that the BC prepared by AC-treated VR hydrolysate had higher fiber density, higher crystallinity, and good thermal stability. Furthermore, the regenerated BC (RBC) fibers with a tensile stress of 400 MPa were prepared successfully using AmimCl solution as a solvent by dry-wet-spinning method. Overall, the VR waste could be used as an alternative carbon source for the sustainable production of BC, which could be further applied to RBC fibers preparation.

Co-production of pigment and high value-added bacterial nanocellulose from Suaeda salsa biomass with improved efficiency of enzymatic saccharification and fermentation

This study evaluated the co-production of pigment and bacterial nanocellulose (BNC) from S. salsa biomass. The extraction of the beet red pigment reduced the salts and flavonoids contents by 82.7%-100%, promoting the efficiencies of enzymatic saccharification of the biomass and the fermentation of BNC from the hydrolysate. SEM analysis revealed that the extraction process disrupted the lignocellulosic fiber structure, and the chemical analysis revealed the lessened cellulase inhibitors, consequently facilitating enzymatic saccharification for 10.4 times. BNC producing strains were found to be hyper-sensitive to NaCl stress, produced up to 400.4% more BNC from the hydrolysate after the extraction. The fermentation results of BNC indicated that the LDU-A strain yielded 2.116 g/L and 0.539 g/L in ES-M and NES-M, respectively. In comparison to the control, the yield in ES-M increased by approximately 20.0%, while the enhancement in NES-M was more significant, reaching 292.6%. After conducting a comprehensive characterization of BNC derived from S. salsa through Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Thermogravimetric Analysis (TGA), the average fiber diameter distribution of these four BNC materials ranges from 22.23 to 33.03 nanometers, with a crystallinity range of 77%-90%. Additionally, they exhibit a consistent trend during the thermal degradation process, further emphasizing their stability in high-temperature environments and similar thermal properties. Our study found an efficient co-production approach of pigment and BNC from S. salsa biomass. Pigment extraction made biomass more physically and chemically digestible to cellulase, and significantly improved BNC productivity and quality.

Overlooked Promising Green Features of Electrospun Cellulose-Based Fibers in Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are accounted as promising power tools, applicable in a wide range of energy-based equipment, from portable devices to electric vehicles. Meanwhile, approaching a cost-effective, environmentally friendly, and safe LIB array has remained sluggish yet. In this regard, cellulose, as a nontoxic natural renewable polymer, has provided a stable and cohesive electrode structure with excellent mechanical stability and reduced electrode cracking or delamination during cycling. Additionally, the porous configuration of the cellulose allows for efficient and faster ion transport as a separator component. Miniaturizing cellulose and its derivatives have revealed more fabulous characteristics for the anode, cathode, and separator resulting from the increased surface-to-volume ratio and superior porosity, as well as their thin and lightweight architectures. The focal point of this review outlines the challenges relating to the extraction and electrospinning of cellulose-based nanofibers. Additionally, the efforts to employ these membranes as the LIBs' components are elucidated. Correspondingly, despite the great performance of cellulose-based LIB structures, a research gap is sensed in this era, possibly due to the difficulties in processing the electrospun cellulose fibers. Hence, this review can provide a source of recent advancements and innovations in cellulose-based electrospun LIBs for researchers who aim to develop versatile battery structures using green materials, worthwhile, and eco-friendly processing techniques.

Bioconversion of underutilized brewing by-products into bacterial cellulose by a newly isolated Komagataeibacter rhaeticus strain: A preliminary evaluation of the bioprocess environmental impact

A novel Komagataeibacter rhaeticus UNIWA AAK2 strain was used to produce bacterial cellulose (BC), valorizing brewers' spent grain (BSG) and brewer's spent yeast (BSY). Under optimal conditions (controlled pH = 6 and 30 g/L sugars), a maximum BC of 4.0 g/L was achieved when BSG aqueous extract (BSGE) was used. The substitution of yeast extract and peptone with BSY autolyzates did not show significant differences on BC concentration and productivity. The FTIR, SEM, and TGA analyses showed that the use of brewing by-products had no effect on the structure and thermal stability of the produced BC, compared to highly-pure and commercial substrates. The LCA of the developed bioprocess revealed that BSGE- and BSY-based media can reduce the carbon footprint of 1 kg dry BC by 76% compared to commercial-based-media. Beer by-products could serve as cost-effective resources to produce value-added and sustainable biopolymers such as BC, while minimizing waste and restructuring the brewing-industry.

The bacterial succession and its role in flavor compounds formation during the fermentation of cigar tobacco leaves

Fermentation is the key process required for developing the characteristic properties of cigar tobacco leaves, complex microorganisms are involved in this process. However, the microbial fermentation mechanisms during the fermentation process have not been well-characterized. This study investigated the dynamic changes in conventional chemical composition, flavor compounds, and bacterial community during the fermentation of cigar tobacco leaves from Hainan and Sichuan provinces in China, as well as the potential roles of bacteria. Fermentation resulted in a reduction of conventional chemical components in tobacco leaves, with the exception of a noteworthy increase in insoluble protein content. Furthermore, the levels of 10 organic acids and 19 amino acids showed a significant decrease, whereas the concentration of 30 aromatic substances exhibited a unimodal trend. Before fermentation, the bacterial community structures and dominant bacteria in Hainan and Sichuan tobacco leaves differed significantly. As fermentation progressed, the community structures in the two regions became relatively similar, with Delftia, Ochrobactrum, Rhodococcus, and Stenotrophomonas being dominant. Furthermore, a total of 12 functional bacterial genera were identified in Hainan and Sichuan tobacco leaves using bidirectional orthogonal partial least squares (O2PLS) analysis. Delftia, Ochrobactrum, and Rhodococcus demonstrated a significant negative correlation with oleic acid and linoleic acid, while Stenotrophomonas and Delftia showed a significant negative correlation with undesirable amino acids, such as Ala and Glu. In addition, Bacillus showed a positive correlation with benzaldehyde, while Kocuria displayed a positive correlation with 2-acetylfuran, isophorone, 2, 6-nonadienal, and β-damascenone. The co-occurrence network analysis of microorganisms revealed a prevalence of positive correlations within the bacterial network, with non-abundant bacteria potentially contributing to the stabilization of the bacterial community. These findings can improve the overall tobacco quality and provide a novel perspective on the utilization of microorganisms in the fermentation of cigar tobacco leaves.

From Nature to Lab: Sustainable Bacterial Cellulose Production and Modification with Synthetic Biology

Bacterial cellulose (BC) is a macromolecule with versatile applications in medicine, pharmacy, biotechnology, cosmetology, food and food packaging, ecology, and electronics. Although many bacteria synthesize BC, the most efficient BC producers are certain species of the genera Komagataeibacter and Novacetimonas. These are also food-grade bacteria, simplifying their utilization at industrial facilities. The basic principles of BC synthesis are known from studies of Komagataeibacter xylinus, which became a model species for studying BC at genetic and molecular levels. Cellulose can also be of plant origin, but BC surpasses its purity. Moreover, the laboratory production of BC enables in situ modification into functionalized material with incorporated molecules during its synthesis. The possibility of growing Komagataeibacter and Novacetimonas species on various organic substrates and agricultural and food waste compounds also follows the green and sustainable economy principles. Further intervention into BC synthesis was enabled by genetic engineering tools, subsequently directing it into the field of synthetic biology. This review paper presents the development of the fascinating field of BC synthesis at the molecular level, seeking sustainable ways for its production and its applications towards genetic modifications of bacterial strains for producing novel types of living biomaterials using the flexible metabolic machinery of bacteria.

Modification of microstructure and selected physicochemical properties of bacterial cellulose produced by bacterial isolate using hydrocolloid-fortified Hestrin-Schramm medium

Bacterial cellulose (BC) is a biopolymer with applications in numerous industries such as food and pharmaceutical sectors. In this study, various hydrocolloids including modified starches (oxidized starch-1404 and hydroxypropyl starch-1440), locust bean gum, xanthan gum (XG), guar gum, and carboxymethyl cellulose were added to the Hestrin-Schramm medium to improve the production performance and microstructure of BC by Gluconacetobacter entanii isolated from coconut water. After 14-day fermentation, medium supplemented with 0.1% carboxymethyl cellulose and 0.1% XG resulted in the highest BC yield with dry BC content of 9.82 and 6.06 g/L, respectively. In addition, scanning electron microscopy showed that all modified films have the characteristic three-dimensional network of cellulose nanofibers with dense structure and low porosity as well as larger fiber size compared to control. X-ray diffraction indicated that BC fortified with carboxymethyl cellulose exhibited lower crystallinity while Fourier infrared spectroscopy showed characteristic peaks of both control and modified BC films.

Producing bacterial cellulose from industrial recycling paper waste sludge

This study aimed to produce bacterial cellulose from paper waste sludge (PWS) as a method of utilizing the cellulose source from the remaining pulp in the material. Initially, PWS was hydrolyzed by sulfuric acid to create an enriched-reducing sugar hydrolysate. One-factor experiments were conducted with a fixed amount of PWS (5 g) to investigate the influence of hydrolysis conditions, including water, sulfuric acid addition, temperature, and retention time, on the production yield of reducing sugars. Based on these results, the Box-Behnken model was designed to optimize the hydrolysis reaction. The optimal hydrolysis conditions were 10 ml/g of the sulfuric acid solution (30.9%) at 105.5 °C for 90 min of retention time 0.81 (gGE/g PWS), corresponding to a conversion yield of 40.5%). Subsequently, 100 ml of the filtered and neutralized PWS hydrolysate was used as the culture to produce the bacterial cellulose (BC) using Acetobacter xylinum, which produced 12 g/L of bacterial cellulose. The conversion yield of bacterial cellulose calculated as the ratio of the weight of produced bacterial cellulose to that of cellulose in PWS reached 33.3%. The structure of the obtained BC was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) to indicate the formation of nano-cellulose fiber networks. This research proposed a combined method to convert paper waste sludge into bacterial cellulose, demonstrating the potential for waste utilization and sustainable production of paper industries for added-value products.

Insight into the Latest Medical Applications of Nanocellulose

Nanocelluloses (NCs) are appealing nanomaterials that have experienced rapid development in recent years, with great potential in the biomedical field. This trend aligns with the increasing demand for sustainable materials, which will contribute both to an improvement in wellbeing and an extension of human life, and with the demand to keep up with advances in medical technology. In recent years, due to the diversity of their physical and biological properties and the possibility of tuning them according to the desired goal, these nanomaterials represent a point of maximum interest in the medical field. Applications such as tissue engineering, drug delivery, wound dressing, medical implants or those in cardiovascular health are some of the applications in which NCs have been successfully used. This review presents insight into the latest medical applications of NCs, in the forms of cellulose nanocrystals (CNCs), cellulose nanofibers (CNFs) and bacterial nanocellulose (BNC), with an emphasis on the domains that have recently experienced remarkable growth, namely wound dressing, tissue engineering and drug delivery. In order to highlight only the most recent achievements, the presented information is focused on studies from the last 3 years. Approaches to the preparation of NCs are discussed either by top-down (chemical or mechanical degradation) or by bottom-up (biosynthesis) techniques, along with their morphological characterization and unique properties, such as mechanical and biological properties. Finally, the main challenges, limitations and future research directions of NCs are identified in a sustained effort to identify their effective use in biomedical fields.

Essential characteristics improvement of metallic nanoparticles loaded carbohydrate polymeric films - A review

Petroleum-based films have contributed immensely to various environmental issues. Developing green-based films from carbohydrate polymers is crucial for addressing the harms encountered. However, some limitations exist on their property, processibility, and applicability that prohibit their processing for further developments. This review discusses the potential carbohydrate polymers and their sources, film preparation methods, such as solvent-casting, tape-casting, extrusion, and thermo-mechanical compressions for green-based films using various biological polymers with their merits and demerits. Research outcomes revealed that the essential characteristics improvement achieved by incorporating different metallic nanoparticles has significantly reformed the properties of biofilms, including crystallization, mechanical stability, thermal stability, barrier function, and antimicrobial activity. The property-enhanced bio-based films made with nanoparticles are potentially interested in replacing fossil-based films in various areas, including food-packaging applications. The review paves a new way for the commercial use of numerous carbohydrate polymers to help maintain a sustainable green environment.

Acetic acid bacteria in agro-wastes: from cheese whey and olive mill wastewater to cellulose

In this study, cheese whey and olive mill wastewater were investigated as potential feedstocks for producing bacterial cellulose by using acetic acid bacteria strains. Organic acids and phenolic compounds composition were assayed by high-pressure liquid chromatography. Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction were used to investigate modifications in bacterial cellulose chemical and morphological structure. Cheese whey was the most efficient feedstock in terms of bacterial cellulose yield (0.300 g of bacterial cellulose/gram of carbon source consumed). Bacterial cellulose produced in olive mill wastewater presented a more well-defined network compared to pellicles produced in cheese whey, resulting in a smaller fiber diameter in most cases. The analysis of bacterial cellulose chemical structure highlighted the presence of different chemical bonds likely to be caused by the adsorption of olive mill wastewater and cheese whey components. The crystallinity ranged from 45.72 to 80.82%. The acetic acid bacteria strains used in this study were characterized by 16S rRNA gene sequencing, allowing to assign them to Komagataeibacter xylinus and Komagataeibacter rhaeticus species. This study proves the suitability to perform sustainable bioprocesses for producing bacterial cellulose, combining the valorisation of agro-wastes with microbial conversions carried out by acetic acid bacteria. The high versatility in terms of yield, morphology, and fiber diameters obtained in cheese whey and olive mill wastewater contribute to set up fundamental criteria for developing customized bioprocesses depending on the final use of the bacterial cellulose. KEY POINTS: • Cheese whey and olive mill wastewater can be used for bacterial cellulose production. • Bacterial cellulose structure is dependent on the culture medium. • Komagataeibacter strains support the agro-waste conversion in bacterial cellulose.

Bacterial cellulose production by a strain of Komagataeibacter rhaeticus isolated from residual loquat

In this study, loquat extract was selected as a promising substrate for bacterial cellulose (BC) production. A new BC-producing bacterial strain was isolated from residual loquat and identified as Komagataeibacter rhaeticus. BC production with different carbon sources and with loquat extract was investigated. Among all tested carbon sources, glucose was demonstrated to be the best substrate for BC production by K. rhaeticus, with up to 7.89 g/L dry BC obtained under the optimal initial pH (5.5) and temperature (28 °C) with 10 days of fermentation. The total sugar and individual sugars were investigated in different loquat extracts, in which fructose, glucose, and sucrose were the three main sugars. When loquat extract was prepared with a solid‒liquid (S-L) ratio of 2:1, the concentrations of glucose, fructose, and sucrose were 7.91 g/L, 9.31 g/L, and 2.84 g/L, respectively. The BC production obtained from loquat extract was higher than that of other carbon sources except glucose, and 6.69 g/L dry BC was obtained from loquat extract with an S-L ratio of 2:1. After BC production, all sugars substantially decreased, with the utilization of glucose, fructose, and sucrose reaching 93.9%, 87.9%, and 100%, respectively. These results suggested that the different sugars in loquat extract were all carbon sources participating in BC production by K. rhaeticus. Structural and physicochemical properties were investigated by SEM, TGA, XRD, and FT-IR spectroscopy. The results showed that the structural, chemical group, and water holding capacity of BC obtained from loquat extract were similar to those of BC obtained from glucose, but the crystallinity and thermal stability of BC were higher than those of BC from mannose and lactose but lower than those of BC from glucose and fructose. KEY POINTS: • A new BC-producing strain was isolated and identified as Komagataeibacter rhaeticus. • Loquat extract is an alternative substrate for BC production. • The BC obtained from loquat extract owns advanced physicochemical properties.

Wastewater from the Arenga Starch Industry as a Potential Medium for Bacterial Cellulose and Cellulose Acetate Production

Wastewater from the Arenga starch industry (WWAS) contains a high chemical oxygen demand (COD) concentration, so it has to be treated before being discharged into water bodies. Therefore, the purpose of this study was to utilize WWAS as a medium for bacterial cellulose (BC) and cellulose acetate (CA) production. This study consisted of the production of BC through fermentation and the production of CA through acetylation. Fermentation was conducted under static batch conditions with various initial pHs and sucrose additions, while acetylation was conducted with various BC-acetic anhydride ratios. The results of this study showed that the maximum BC production of 505.6 g/L of the culture medium was obtained under the optimal conditions of a sucrose addition of 200 g/L, an initial medium pH of 4.5, and a cultivation time of 14 d. Furthermore, a BC-acetic anhydride ratio of 1:3 resulted in CA being suitable as a biofilm raw material with a yield of 81.49%, an acetyl content of 39.82%, a degree of substitution of 2.456, and a degree of crystallinity of 36.7%. FT-IR, ¹H and ¹³C NMR, XRD, and SEM analyses confirmed the successful process of acetylation of BC to CA.

Exploitation of cantaloupe peels for bacterial cellulose production and functionalization with green synthesized Copper oxide nanoparticles for diverse biological applications

The promising features of most bacterial celluloses (BC) promote the continuous mining for a cost-effective production approach toward wide and sustainable applications. Herein, cantaloupe peels (CP) were successfully implemented for sustainable BC production. Results indicated that the enzymatically hydrolyzed CP supported the maximum BC production of approximately 3.49 g/L when used as a sole fermentation media. The produced BC was fabricated with polyvinyl alcohol (PVA) and chitosan (Ch), and loaded with green synthesized copper oxide nanoparticles (CuO-NPs) to improve its biological activity. The novel composite showed an antimicrobial activity against several human pathogens such as Staphylococcus aureus, Streptococcus mutans, Salmonella typhimurium, Escherichia coli, and Pseudomonas fluorescens. Furthermore, the new composite revealed a significant in vitro anticancer activity against colon (Caco-2), hepatocellular (HepG-2), and breast (MDA) cancer cells, with low IC50 of 0.48, 0.27, and 0.33 mg/mL for the three cell lines, respectively. On the other hand, the new composite was remarkably safe for human skin fibroblast (HSF) with IC50 of 1.08 mg/mL. Interestingly, the composite membranes exhibited lethal effects against all stages of larval instar and pupal stage compared with the control. In this study, we first report the diverse potential applications of BC/PVA/Ch/CuO-NPs composites based on green synthesized CuO-NPs and sustainably produced BC membrane.

Fabrication of biodegradable chicken feathers into ecofriendly-functionalized biomaterials: characterization and bio-assessment study

This study aims to investigate novel applications for chicken feather waste hydrolysate through a green, sustainable process. Accordingly, an enzymatically degraded chicken feather (EDCFs) product was used as a dual carbon and nitrogen source in the production medium of bacterial cellulose (BC). The yield maximization was attained through applying experimental designs where the optimal level of each significant variable was recorded and the yield rose 2 times. The produced BC was successfully characterized by FT-IR, XRD and SEM. On the other hand, sludge from EDCFs was used as a paper coating agent. The mechanical features of the coated papers were evaluated by bulk densities, maximum load, breaking length, tensile index, Young's modulus, work to break and coating layer. The results showed a decrease in tensile index and an increase in elongation at break. These indicate more flexibility of the coated paper. The coated paper exhibits higher resistance to water vapor permeability and remarkable oil resistance compared to the uncoated one. Furthermore, the effectiveness of sludge residue in removing heavy metals was evaluated, and the sorption capacities were ordered as Cu ++  > Fe ++  > Cr ++  > Co ++ with high affinity (3.29 mg/g) toward Cu ++ and low (0.42 mg/g) towards Co ++ in the tested metal solution.

Fabrication of efficient protein imprinted materials based on pearl necklace-like MOFs bacterial cellulose composites

The acquisition of efficient protein isolation substances is vital for proteomic research, whereas it's still challenging nowadays. Herein, an elaborately designed protein imprinted material based on a bacterial cellulose@ZIF-67 composite carrier (BC@ZIF-67) is proposed for the first time. In particular, due to the ultrafine fiber diameter and abundant hydroxyl functional groups of the bacterial cellulose, BC@ZIF-67 presented a compact arrangement structure similar to a pearl necklace, which greatly promoted template immobilization and mass transfer resistance in protein imprinting technology. Therefore, the protein-imprinted material (BC@ZIF-67@MIPs) fabricated by surface imprinting technology and template immobilization strategy could exhibit ultrahigh adsorption capacity (1017.0 mg g^-1), excellent recognition (IF = 5.98) and rapid adsorption equilibrium time (50 min). In addition, based on the experiment outcomes, our team employed BC@ZIF-67@MIPs to enrich template protein in blended protein solutions and biosamples, identifying them as underlying candidates for isolating and purifying proteins.

Optimization and physicochemical characterization of bacterial cellulose by Komagataeibacter nataicola and Komagataeibacter maltaceti strains isolated from grape, thorn apple and apple vinegars

Bacterial cellulose (BC) is a valuable biopolymer that is increasingly used in medical, pharmaceutical and food industries with its excellent physicochemical properties as high water-holding capacity, nanofibrillar structure, large surface area, porosity, mechanical strength and biocompatibility. Accordingly, the isolation, identification and characterization of potent BC producers from grape, thorn apple and apple vinegars were performed in this study. The strains isolated from grape and apple vinegars were identified as Komagataeibacter maltaceti and the strain isolated from thorn apple vinegar was identified as Komagataeibacter nataicola with 16S rRNA analysis. Optimized conditions were found as 8% dextrin, 1.5% (peptone + yeast extract) and 10% inoculation amount at pH 6.0 with a productivity rate of 1.15 g/d/L, a yield of 8.06% and a dry weight of 6.45 g/L for K. maltaceti, and 10% maltose, 1% (peptone + yeast extract) and 10% inoculation amount at pH 6.0 with a productivity rate of 0.96 g/L/d, a yield of 5.35% and a dry weight of 5.35 g/L for K. nataicola. Obtained BC from K. maltaceti and K. nataicola strains was more than 2.56- and 1.86-fold when compared with BC obtained from HS media and exhibited 95.1% and 92.5% WHC, respectively. Based on the characterization results, BC pellicles show characteristic FT-IR bands and have ultrafine 3D structures with high thermal stability. By means of having ability to assimilate monosaccharides, disaccharides and polysaccharide used in this study, it is predicted that both isolated Komagataeibacter species can be used in the production of biopolymers from wastes containing complex carbon sources in the future.

Bioconversion of Terephthalic Acid and Ethylene Glycol Into Bacterial Cellulose by Komagataeibacter xylinus DSM 2004 and DSM 46604

Komagataeibacter xylinus strains DSM 2004 and DSM 46604 were evaluated for their ability to grow and produce bacterial cellulose (BC) upon cultivation on terephthalic acid (TA) and ethylene glycol (EG), which are monomers of the petrochemical-derived plastic polyethylene terephthalate (PET). Both strains were able to utilize TA, EG, and their mixtures for BC synthesis, with different performances. K. xylinus DSM 2004 achieved higher BC production from TA (0.81 ± 0.01 g/L), EG (0.64 ± 0.02 g/L), and TA + EG mixtures (0.6 ± 0.1 g/L) than strain DSM 46604. The latter was unable to utilize EG as the sole carbon source and reached a BC production of 0.16 ± 0.01 g/L and 0.23 ± 0.1 g/L from TA alone or TA + EG mixtures, respectively. Further supplementing the media with glucose enhanced BC production by both strains. During cultivation on media containing TA and EG, rapid pH drop due to metabolization of EG into acidic compounds led to some precipitation of TA that was impregnated into the BC pellicles. An adaptation of the downstream procedure involving BC dissolution in NaOH was used for the recovery of pure BC. The different medium composition tested, as well as the downstream procedure, impacted the BC pellicles’ physical properties. Although no variation in terms of the chemical structure were observed, differences in crystallinity degree and microstructure of the produced BC were observed. The BC produced by K. xylinus DSM 2004 had a higher crystallinity (19–64%) than that of the strain DSM 46604 (17–53%). Moreover, the scanning electron microscopy analysis showed a higher fiber diameter for K. xylinus DSM 2004 BC (46–56 nm) than for K. xylinus DSM 46604 (37–49 nm). Dissolution of BC in NaOH did not influence the chemical structure; however, it led to BC conversion from type I to type II, as well as a decrease in crystallinity. These results demonstrate that PET monomers, TA and EG, can be upcycled into a value-added product, BC, presenting an approach that will contribute to lessening the environmental burden caused by plastic disposal in the environment.

131I-αPD-L1 immobilized by bacterial cellulose for enhanced radio-immunotherapy of cancer

Radioisotope therapy (RIT) of cancer is restrained by the nonspecific distribution of radioisotope and ineptitude for metastatic tumors. Meanwhile, the clinical application of immune checkpoint blockade (ICB) confronts problems such as low responsive rate, multiple administration requirements and immune-related adverse events (irAE). To address these challenges, we prepared an injectable suspension by immobilizing ¹³¹I-labeled anti-programmed cell death-ligand 1 antibody (αPD-L1) in bacterial cellulose for precise and durable radio-immunotherapy of cancer. The crisscross network structure of bacterial cellulose nanofibers would contribute to the long-term retention of ¹³¹I-labeled αPD-L1 within tumors, which could reduce the side effect stemmed from the nonspecific ¹³¹I distribution in normal tissues. The potent long-term RIT of ¹³¹I, combined with ICB by αPD-L1, could effectively restrain the growth of primary tumor in mice. In addition to the direct killing effect, ¹³¹I-αPD-L1 immobilized by bacterial cellulose could enhance the immunogenic cell death (ICD) of cancer cells, activating the maturation of multiple immune cells to induce a systemic anti-tumor immune effect. Our therapeutic strategy could suppress spontaneous cancer metastasis and prolong the survival time of tumor-bearing mice. This study proposed a new approach for combined radio-immunotherapy and a novel solution for tumor metastasis in advanced-stage cancers.

Bacterial cellulose as a potential biopolymer in biomedical applications: a state-of-the-art review

Throughout history, natural biomaterials have benefited society. Nevertheless, in recent years, tailoring natural materials for diverse biomedical applications accompanied with sustainability has become the focus. With the progress in the field of materials science, novel approaches for the production, processing, and functionalization of biomaterials to obtain specific architectures have become achievable. This review highlights an immensely adaptable natural biomaterial, bacterial cellulose (BC). BC is an emerging sustainable biopolymer with immense potential in the biomedical field due to its unique physical properties such as flexibility, high porosity, good water holding capacity, and small size; chemical properties such as high crystallinity, foldability, high purity, high polymerization degree, and easy modification; and biological characteristics such as biodegradability, biocompatibility, excellent biological affinity, and non-biotoxicity. The structure of BC consists of glucose monomer units polymerized via cellulose synthase in β-1-4 glucan chains, creating BC nano fibrillar bundles with a uniaxial orientation. BC-based composites have been extensively investigated for diverse biomedical applications due to their similarity to the extracellular matrix structure. The recent progress in nanotechnology allows the further modification of BC, producing novel BC-based biomaterials for various applications. In this review, we strengthen the existing knowledge on the production of BC and BC composites and their unique properties, and highlight the most recent advances, focusing mainly on the delivery of active pharmaceutical compounds, tissue engineering, and wound healing. Further, we endeavor to present the challenges and prospects for BC-associated composites for their application in the biomedical field.

Effective bioremediation of tobacco wastewater by microalgae at acidic pH for synergistic biomass and lipid accumulation

Tobacco wastewater is too difficult to decontaminate which poses a significant environmental problem due to the harmful and toxic components. Chlorella pyrenoidosa is a typical microalgal species with potential in removal of organic/inorganic pollutants and proves to be an ideal algal-based system for wastewater treatment. However, the strategy of tobacco related wastewater treatment using microalgae is in urgent need of development. In this study, C. pyrenoidosa was used to evaluate the removal efficiency of artificial tobacco wastewater. Under various solid-to-liquid (g/L) ratios, 1:1 ratio and acidic pH 5.0 were optimal for C. pyrenoidosa to grow with high performance of removal capacity to toxic pollutants (such as COD, NH3-N, nicotine, nitrosamines and heavy metals) with the alleviation of oxidative damage. Algal biomass could reach up to 540.24 mg/L. Furthermore, carbon flux of C. pyrenoidosa was reallocated from carbohydrate and protein biosynthesis to lipogenesis with a high lipid content of 268.60 mg/L at pH 5.0. Overall, this study demonstrates an efficient and sustainable strategy for tobacco wastewater treatment at acidic pH with the production of valuable microalgal products, which provides a promising biorefinery strategy for microalgal-based wastewater bioremediation.

Techno-economic feasibility assessment of bacterial cellulose biofilm production during the Kombucha fermentation process

Bacterial cellulose produced during Kombucha fermentation has recently received lots of attention owing to its desirable mechanical and physicochemical properties and is exploited for different food, textiles and environmental applications. However, lack of information on process feasibility often hinders large-scale manufacturing of Kombucha-based cellulose. Therefore, the current study assesses techno-economic feasibility of a 60-ton annual capacity Kombucha-based cellulose production facility using SuperPro designer. Economic feasibility analysis showed an estimation of 13.72 million US$ as total investment and 3.8 million US$ as operating costs with 89% expenses associated with facility dependent and labour costs. The process feasibility is revealed with a payback time of 4.23 years, 23.64% return on investment and 16.48% internal rate of return. Sensitivity analysis presented that increased volume of fermentation units and automating the process can significantly reduce input costs. Such research is necessary to aid policymakers in facilitating the commercialization of Kombucha-based cellulose at field scale.

Developments in bioprocess for bacterial cellulose production

Bacterial cellulose (BC) represents a novel bio-origin nonomaterial with its unique properties having diverse applications. Increased market demand and low yield are the major reason for its higher cost. Bacteria belonging to Komagataeibacter sp are the most exploited ones for BC production. Development of a cost-effective bioprocess for higher BC production is desirable. Though static fermentation modes have been majorly employed for BC production using tray fermenters, agitated mode has also been employed successfully with air-lift fermenters as well as stirred tank reactors. Bioprocess advances in recent years has led BC production to an upper level; however, challenges of aeration requirement and labor cost towards the higher end is associated with static cultivation at large scale. We have discussed the bioprocess development for BC production in recent years along with the challenges associated and the path forward.

Ecofriendly green biosynthesis and characterization of novel bacteriocin-loaded bacterial cellulose nanofiber from Gluconobacter cerinus HDX-1

A new strain of bacterial cellulose (BC)-producing Gluconobacter cerinus HDX-1 was isolated and identified, and a simple, low-cost complexation method was used to biosynthesis Lactobacillus paracasei 1∙7 bacteriocin BC (BC-B) nanofiber. The structure and antibacterial properties of the nanofibers were evaluated. Solid-state nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) analysis showed that BC and BC-B nanofibers had typical crystalline form of the cellulose I. X-ray photoelectron spectrometer (XPS), scanning electron microscope (SEM) and atomic force microscopy (AFM) revealed that the bacteriocin and BC were successfully compounded, and the structure of BC-B nanofiber was tighter than BC nanofiber, with lower porosity, swelling ratio and water vapor transmission rate (WVTR). The tensile strength and Young's modulus of BC-B nanofibers were 13.28 ± 1.26 MPa and 132.10 ± 4.92 MPa, respectively, higher than that of BC nanofiber (6.12 ± 0.87 MPa and 101.59 ± 5.87 MPa), indicating that bacteriocin enhance the mechanical properties of BC nanofiber. Furthermore, the BC-B nanofibers exhibited significant thermal stability, antioxidant capacity and antibacterial activity than BC nanofiber. Therefore, bacteriocin-loaded BC nanofiber may be used as antimicrobial agents in active food packaging and medical material.

Characterisation of bacterial nanocellulose and nanostructured carbon produced from crude glycerol by Komagataeibacter sucrofermentans

Bacterial nanocellulose (BNC), which has tunable properties, is a precursor of nanostructured energy storage materials; however, the cost of BNC production is challenging. This study uses crude glycerol from the biodiesel industry as a carbon nutrient and first-time carbonised BNC from K. sucrofermentans that is applied in energy storage. From crude glycerol in static cultivation, 6.4 g L^-1 BNC was produced with a high crystallinity index (85%) and tensile properties in comparison to conventionally used pure carbon substrates. Carbon materials were derived from the BNC retained fibrous and crystalline features with disordered porous structures. The electrochemical properties of the carbon materials have a specific capacitance of 140 F g^-1. This study highlights the valorisation of waste glycerol from the biodiesel industry as a substrate for efficient BNC production and the energy storage potential of carbon derived from BNC as renewable energy materials.

Production and purification of 2-phenylethanol by Saccharomyces cerevisiae using tobacco waste extract as a substrate

2-phenylethanol (2-PE), which is extracted naturally from plant or biotechnology processing, is widely used in the food and cosmetics industries. Due to the high cost of 2-PE production, the valorization of waste carbon to produce 2-PE has gained increasing attention. Here, 2-PE was produced by Saccharomyces cerevisiae using tobacco waste extract (TWE) as the substrate. Considering the toxicity of nicotine and its inhibition of 2-PE, the tolerance of S. cerevisiae was first evaluated. The results suggested that the production of 2-PE by S. cerevisiae in TWEs could be carried out at 2·0 mg ml-1 nicotine concentrations and may be inhibited by 1·0 mg ml-1 2-PE. Thus, the compounds in the TWEs prepared at different temperatures were detected, and the results revealed that the TWEs prepared at 140°C contained 2·18 mg ml-1 of nicotine, had total sugar concentrations of 26·8 mg ml-1 and were suitable for 2-PE production. Due to feedback regulation, the 2-PE production was only 1·11 mg ml-1 , and the remaining glucose concentration remained at 13·78 mg ml-1 , which indicated insufficient glucose utilization. Then, in situ product recovery was further implemented to remove this inhibition; the glucose utilization (the remaining concentration decreased to 3·64 mg ml-1 ) increased, and the 2-PE production increased to 1·65 mg ml-1 . The 2-PE produced in the fermentation broth was first isolated by elution from the resin with 75% ethanol and then by removing the impurities with 2·5% activated charcoal, and pure 2-PE was identified by gas chromatography mass spectrometry. The results of this study suggest that TWE could be an alternative carbon source for 2-PE production. This could provide an outlet tobacco waste as well as reducing the price of natural 2-PE, although more strategies need to be explored to improve the production yield of 2-PE by using TWE.

Bio-conversion of kitchen waste into bacterial cellulose using a new multiple carbon utilizing Komagataeibacter rhaeticus: Fermentation profiles and genome-wide analysis

A cellulose-producing bacterium Komagataeibacter rhaeticus K15 was isolated from kombucha tea, and its metabolic pathways and cellulose synthesis operon were analyzed by genome sequencing. Different from the reported K. rhaeticus, the K15 produced little gluconic acid (2.26 g/L) when glucose was the sole carbon source and has the capacity for high cellulose production (4.76 g/L) with other carbon sources. Furthermore, six nitrogen-fixing genes were found to be responsible for the survival of K15 on a nitrogen-free medium. Based on its fermentation characteristics, K15 was cultured in a kitchen waste medium as a strategy for green and sustainable bacterial cellulose production. The SEM, XRD, and FTIR results indicated that synthesized cellulose has a mean diameter of 40-50 nm nanofiber, good crystallinity, and the same chemical structure. The K15 strain provides a highly viable alternative strategy to reduce the costs of bacterial cellulose production using agro-industrial residues as nutrient sources.

Genetic modification for enhancing bacterial cellulose production and its applications

Bacterial cellulose (BC) is higher in demand due to its excellent properties which is attributed to its purity and nano size. Komagataeibacter xylinum is a model organism where BC production has been studied in detail because of its higher cellulose production capacity. BC production mechanism shows involvement of a series of sequential reactions with enzymes for biosynthesis of cellulose. It is necessary to know the mechanism to understand the involvement of regulatory proteins which could be the probable targets for genetic modification to enhance or regulate yield of BC and to alter BC properties as well. For the industrial production of BC, controlled synthesis is desired so as to save energy, hence genetic manipulation opens up avenues for upregulating or controlling the cellulose synthesis in the bacterium by targeting genes involved in cellulose biosynthesis. In this review article genetic modification has been presented as a tool to introduce desired changes at genetic level resulting in improved yield or properties. There has been a lack of studies on genetic modification for BC production due to limited availability of information on whole genome and genetic toolkits; however, in last few years, the number of studies has been increased on this aspect as whole genome sequencing of several Komagataeibacter strains are being done. In this review article, we have presented the mechanisms and the targets for genetic modifications in order to achieve desired changes in the BC production titer as well as its characteristics.

In-situ fermentation with gellan gum adding to produce bacterial cellulose from traditional Chinese medicinal herb residues hydrolysate

In this study, bacterial cellulose was synthesized by Taonella mepensis from traditional Chinese medicinal herb residues hydrolysate. To overcome the inhibitory effect of fermentation environment, in-situ fermentation with gellan gum adding was carried out for the first time. After 10 days' static fermentation, both high-acyl gellan gum and low-acyl gellan gum adding showed certain beneficial effects for bacterial cellulose production that the highest bacterial cellulose yield (0.866 and 0.798 g/L, respectively) was 59% and 47% higher than that (0.543 g/L) without gellan gum adding. Besides, gellan gum based bacterial cellulose showed some better texture characteristics. Gellan gum was loaded in the nano network of bacterial cellulose, and gellan gum adding had some influence on the crystal structure and thermal degradation behaviors of bacterial cellulose but affected little on its functional groups. Overall, this in-situ fermentation technology is attractive for bacterial cellulose production from low-cost but inhibitory substrates.