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

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.

Advanced manufacture of polyphenols, essential oils and bacterial cellulose in a novel citrus processing wastewater biorefinery

Herein, a citrus processing wastewater-based biorefinery has been developed manufacturing essential oils, polyphenols and bacterial cellulose. Liquid-liquid extraction was evaluated for isolation of essential oils assessing different organic solvents, recovering 0.45 kg of essential oils per m3 of wastewater using n-heptane. Amberilte® XAD4, XAD16N and XAD7HP, PurSorb™ PAD900, biochar and activated biochar were compared as adsorbents for polyphenols recovery, demonstrating that the adsorption isotherms of the resins applied could be closely predicted using the Langmuir model. Adsorption and desorption density experiments exhibited that the phenolic content present in citrus processing wastewater could be efficiently recovered using PAD900, yielding 0.78 kg of polyphenols per m3 of wastewater. The sugar content remaining following polyphenols adsorption was applied for bacterial cellulose production employing Komagataeibacter sucrofermentans DSM 15973 determining the biopolymer's production efficiency as well as morphological and structural properties at different carbon to free amino nitrogen ratios. The higher content of the biomaterial was obtained employing 15.0 carbon to free amino nitrogen ratio, which yielded 4.4 kg of biopolymer per m3 of wastewater. The study has shown that by decreasing the carbon to free amino nitrogen ratio could enable enhancing the water-holding capacity of bacterial cellulose, exhibiting that the control of fermentation conditions could potentially enable tailoring the properties of the biomaterial for certain industrial applications. The bioactive, antioxidant and preservative properties of essential oils and polyphenols constitute the aforementioned products significant for a range of industrial applications within the pharmaceutical, cosmetics and food sectors.

Efficient pectin recovery from sugar beet pulp as effective bio-based coating for Pacific white shrimp preservation

This study demonstrates the valorization of sugar beet pulp (SBP)-derived pectin to produce bio-based coatings for shrimp preservation. Pectin extraction was assessed at varying temperatures and extraction times to achieve tailored properties (high methoxyl-pectins, degree of esterification-DE >79.0 %) leading to 11.5 % extraction yield, 78.1 % galactouronic acid content and 80 % DE at optimal conditions (pH 1.5, 80 °C, 2 h). Pectin-based coatings supplemented with ascorbic acid (AA) (0.5-2.0 %) led to organoleptically acceptable shrimps with significantly lower total color differences during 28-days of storage, compared to uncoated and pectin-coated counterparts. AA-based coatings delayed shrimp melanosis, expressed as reduced polyphenoloxidase activity (48-86 %). Rich-in-holocellulose solids derived after pectin extraction were used for bacterial cellulose (BC) production, pinpointing the SBP potential as a multi-purpose feedstock. Fed-batch fermentation enhanced BC concentration (by 110 %) and productivity (1.6-fold higher) compared to batch-cultures. Pectin produced within a SBP-based biorefinery could be applied as bio-based coating with food packaging potential.

Biotechnology in Food Packaging Using Bacterial Cellulose

Food packaging, which is typically made of paper/cardboard, glass, metal, and plastic, is essential for protecting and preserving food. However, the impact of conventional food packaging and especially the predominant use of plastics, due to their versatility and low cost, bring serious environmental and health problems such as pollution by micro and nanoplastics. In response to these challenges, biotechnology emerges as a new way for improving packaging by providing biopolymers as sustainable alternatives. In this context, bacterial cellulose (BC), a biodegradable and biocompatible material produced by bacteria, stands out for its mechanical resistance, food preservation capacity, and rapid degradation and is a promising solution for replacing plastics. However, despite its advantages, large-scale application still encounters technical and economic challenges. These include high costs compared to when conventional materials are used, difficulties in standardizing membrane production through microbial methods, and challenges in optimizing cultivation and production processes, so further studies are necessary to ensure food safety and industrial viability. Thus, this review provides an overview of the impacts of conventional packaging. It discusses the development of biodegradable packaging, highlighting BC as a promising biopolymer. Additionally, it explores biotechnological techniques for the development of innovative packaging through structural modifications of BC, as well as ways to optimize its production process. The study also emphasizes the importance of these solutions in promoting a circular economy within the food industry and reducing its environmental impact.

Recent advancements in development and application of microbial cellulose in food and non-food systems

Microbial cellulose is a fermented form of very pure cellulose with a fibrous structure. The media rich in glucose or other carbon sources are fermented by bacteria to produce microbial cellulose. The bacteria use the carbon to produce cellulose, which grows as a dense, gel-like mat on the surface of the medium. The product was then collected, cleaned, and reused in various ways. The properties of microbial cellulose, such as water holding capacity, gas permeability, and ability to form a flexible, transparent film make it intriguing for food applications. Non-digestible microbial cellulose has been shown to improve digestive health and may have further advantages. It is also very absorbent, making it a great option for use in wound dressings. The review discusses the generation of microbial cellulose and several potential applications of microbial cellulose in fields including pharmacy, biology, materials research, and the food industry.

Utilization of the sugar fraction from Arabica coffee pulp as a carbon source for bacteria producing cellulose and cytotoxicity with human keratinocyte

Coffee pulp (CP), a by-product of coffee production, is an underutilized resource with significant potential value. CP contains monosaccharides that can serve as an ideal carbon source for bacterial cultivation, enabling the production of value-added components such as medical-grade cellulose. Herein, we extracted the sugar fraction from Arabica CP and used it as a supplement in a growing media of a bacteria cellulose (BC), Komagataeibacter nataicola. The BC was then characterized and tested for cytotoxicity. The CP sugar fraction yielded approximately 7% (w/w) and contained glucose at 4.52 mg/g extract and fructose at 7.34 mg/g extract. Supplementing the sugar fraction at different concentrations (0.1, 0.3, 0.5, 0.7, and 1 g/10 mL) in sterilized glucose yeast extract broth, the highest yield of cellulose (0.0020 g) occurred at 0.3 g/10 mL. It possessed similar physicochemical attributes to the BC using glucose, with some notable improvements in fine structure and arrangement of the functional groups. In cytotoxicity assessments on HaCaT keratinocyte cells, bacterial cellulose concentrations of 2-1000 µg/mL exhibited viability of ≥ 80%. However, higher concentrations were toxic. This research innovatively uses coffee pulp for bacterial cellulose, aligning with the principles of a bio-circular economy that focuses on sustainable biomass utilization.

A sustainable bioprocess to produce bacterial cellulose (BC) using waste streams from wine distilleries and the biodiesel industry: evaluation of BC for adsorption of phenolic compounds, dyes and metals

BACKGROUND

The main challenge for large-scale production of bacterial cellulose (BC) includes high production costs interlinked with raw materials, and low production rates. The valorization of renewable nutrient sources could improve the economic effectiveness of BC fermentation while their direct bioconversion into sustainable biopolymers addresses environmental pollution and/or resource depletion challenges. Herein a green bioprocess was developed to produce BC in high amounts with the rather unexplored bacterial strain Komagataeibacter rhaeticus, using waste streams such as wine distillery effluents (WDE) and biodiesel-derived glycerol. Also, BC was evaluated as a bio-adsorbent for phenolics, dyes and metals removal to enlarge its market diversification.

RESULTS

BC production was significantly affected by the WDE mixing ratio (0-100%), glycerol concentration (20-45 g/L), type of glycerol and media-sterilization method. A maximum BC concentration of 9.0 g/L, with a productivity of 0.90 g/L/day and a water holding capacity of 60.1 g water/g dry BC, was achieved at 100% WDE and ≈30 g/L crude glycerol. BC samples showed typical cellulose vibration bands and average fiber diameters between 37.2 and 89.6 nm. The BC capacity to dephenolize WDE and adsorb phenolics during fermentation reached respectively, up to 50.7% and 26.96 mg gallic acid equivalents/g dry BC (in-situ process). The produced BC was also investigated for dye and metal removal. The highest removal of dye acid yellow 17 (54.3%) was recorded when 5% of BC was applied as the bio-adsorbent. Experiments performed in a multi-metal synthetic wastewater showed that BC could remove up to 96% of Zn and 97% of Cd.

CONCLUSIONS

This work demonstrated a low-carbon approach to produce low-cost, green and biodegradable BC-based bio-adsorbents, without any chemical modification. Their potential in wastewater-treatment-applications was highlighted, promoting closed-loop systems within the circular economy era. This study may serve as an orientation for future research towards competitive or targeted adsorption technologies for wastewater treatment or resources recovery.