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

Bacterial Cellulose for Scalable and Sustainable Bio-Gels in the Circular Economy

Microbial-derived materials are emerging for applications in biomedicine, sensors, food, cosmetics, construction, and fashion. They offer considerable structural properties and process reproducibility compared to other bio-based materials. However, challenges related to efficient and sustainable large-scale production of microbial-derived materials must be addressed to exploit their potential fully. This review analyzes the synergistic contribution of circular, sustainable, and biotechnological approaches to enhance bacterial cellulose (BC) production and fine-tune its physico-chemical properties. BC was chosen as an ideal example due to its mechanical strength and chemical stability, making it promising for industrial applications. The review discusses upcycling strategies that utilize waste for microbial fermentation, simultaneously boosting BC production. Additionally, biotechnology techniques are identified as key to enhance BC yield and tailor its physico-chemical properties. Among the different areas where cellulose-based materials are employed, BC shows promise for mitigating the environmental impact of the garment industry. The review emphasizes that integrating circular and biotechnological approaches could significantly improve large-scale production and enhance the tunability of BC properties. Additionally, these approaches may simultaneously provide environmental benefits, depending on their future progresses. Future advancements should prioritize circular fermentation and biotechnological techniques to expand the potential of BC for sustainable industrial applications.

Upcycling of tea processing waste into kombucha-derived bioactive cellulosic composite for prospective wound dressing action

The aim of the study was to utilize kombucha-derived bacterial cellulosic sheet [KBC], formed as a by-product of fermented, sugared black tea (in the presence of a symbiotic culture of bacteria and yeast), for potential wound dressing applications. KBC was functionalized using aqueous and ethanolic extracts of different phytochemical agents using two ex-situ methods- casting and impregnation. It was observed that casted KBC functionalized with ethanolic extract of Turmeric (1.2% w/w) yielded a maximum zone of inhibition (24.37 ± 0.42 mm) against Pseudomonas aeruginosa. The hemocompatibility test confirmed the composite's biocompatible nature as the percentage hemocompatibility was found to be less than 5%. The MTT assay established its viability and anti-cancerous properties with Turmeric extract loaded KBC showing higher efficiency compared to Tulsi extract. FTIR analysis and SEM imaging confirmed the functionalization of cellulose sheets and the change in morphology. The contact angle analysis showed improved hydrophilic properties of the sheets for absorbing wound exudates, and the water absorption study revealed maximum absorptivity of up to 321.20 ± 6.23%. Thus, it can be concluded from the study that tea processing waste can be reused to produce a value-added product that can act as an efficient, cost-effective biomaterial for wound dressing applications.

Norfloxacin adsorption by torrefied coco peat biochar as a novel adsorbent in a circular economy framework

The current study reported torrefied coco-peat biochar treated at 200 °C, as a novel adsorbent exhibiting phenomenal norfloxacin (NFX) adsorption efficiency. The CHNS analysis confirmed the carbon abundance in the biochar (36.45%), however, XRF analysis indicated a significant presence of K2O (27.73%) and chlorine (7.49%). The XRD and Raman spectral analysis confirmed the amorphous structure of the biochar. Multilayer topology was evident in the SEM micrograph of biochar contributing to its large effective surface area. Additionally, the mesoporous structure of the adsorbent was verified by BET. The adsorption mechanism was predicted to be non-ionic since the zeta potential of both adsorbent and adsorbate was found negative. The process parameters were optimized at 30 °C, pH 6.9, dosage 7 g/L, antibiotic load 494.25 mg/L, and time of 89 min for a maximum of 99.52% adsorption of NFX using Central Composite Design, Analysis of Variance, and Response Surface Methodology. The adsorption process was exothermic, and spontaneous obeying the pseudo-second-order kinetics, while the bulk process was confined to surface adsorption. Isotherm study of NFX adsorption revealed the process to be a favorable, monolayer, and homogeneous adsorption. The NFX molecules were desorbed with an efficiency of 89.19% using 80% ethanol and upon recrystallization, 87.76% of the initial NFX was recovered as crude crystal. Moreover, the NFX removal efficiency was consistent across various water systems, tap water (99.02%), seawater (99.56%), river water (98.92%), pond water (98.26%), and distilled water (99.17%). The techno-economic analysis identified bulk expense as the biochar preparation ($0.82/kg) and the process will be profitable having recovered NFX sold at $6/kg instead of the present retail price ($71/kg). Thus, the study successfully demonstrated a zero-waste, self-sustainable, and revenue-generating water treatment process implementing the circular economy framework.

An overview of bio-cellulose derived materials for catalytic water treatment

Bio-cellulose derived materials (BCM) exhibit distinct structural and morphologic properties, which make them suitable for catalytic environmental remediation. In the domain of water treatment, the prospects for BCM remain bright, offering new possibilities for the development of advanced materials with low environmental impact. Research on BCM as catalysts or catalyst immobilization platforms for water treatment is still limited, mostly using laboratory-grown biomaterials for the photocatalytic degradation of dyes. BCM production costs can be significant, which can hinder its application. Thus, cost-effective alternatives using waste materials as substrates for BCM culture media are highly desirable to optimize production, while also decreasing food waste. Moreover, advances in biotechnology can enhance BCM production, tailoring its properties to meet specific requirements. Hybrid catalytic BCM composites can be easily developed, due to the straightforward functionalization of the biomaterial's network, promoting the efficiency of a variety of catalytic systems. Still considering the intrinsic features of the biomaterial, membrane development and application pose as an opportunity for continuous flow evaluations, facilitating long-term usage and reusability. Nevertheless, there are still challenges regarding catalytic BCM for water treatment (i.e., cost-effectiveness, scaling up, and consistent performance in diverse treatment scenarios). Addressing these aspects can lead to innovative environmental remediation options.

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.

A strategy to maximize astaxanthin production from Haematococcus pluvialis in a cost-effective process by utilizing a PBR-LGP-PBR array (PLPA) hybrid system using light guide panel (LGP) and solar cells

This study evaluated economic feasibility through production efficiency, return on investment (ROI) and payout time of a hybrid system using a photobioreactor (PBR)-light guide panel (LGP)-PBR array (PLPA) and solar cells developed for astaxanthin and ω-3 FA simultaneous production of Haematococcus pluvialis. The economic feasibility of the PLPA hybrid system (8 PBRs) and the PBR-PBR-PBR array (PPPA) system (8 PBRs) was evaluated for producing high-value products while effectively reducing CO₂. Introducing a PLPA hybrid system has increased the amount of culture per area by 1.6 times. Also, the shading effect was effectively suppressed with an LGP placed between each PBR, increasing biomass and astaxanthin productivity by 3.39-fold and 4.79-fold, respectively compared to the untreated H. pluvialis cultures. In addition, ROI increased by 6.55 and 4.71 times, and the payout time was reduced by 1.34 and 1.37 times, respectively in 10 and 100-ton scale processes.

Advances in the Production of Biomaterials through Kombucha Using Food Waste: Concepts, Challenges, and Potential

In recent years, several researchers have focused their studies on the development of sustainable biomaterials using renewable sources, including the incorporation of living biological systems. One of the best biomaterials is bacterial cellulose (BC). There are several ways to produce BC, from using a pure strain to producing the fermented drink kombucha, which has a symbiotic culture of bacteria and yeasts (SCOBY). Studies have shown that the use of agricultural waste can be a low-cost and sustainable way to create BC. This article conducts a literature review to analyze issues related to the creation of BC through kombucha production. The databases used were ScienceDirect, Scopus, Web of Science, and SpringerLink. A total of 42 articles, dated from 2018 to 2022, were referenced to write this review. The findings contributed to the discussion of three topics: (1) The production of BC through food waste (including patents in addition to the scientific literature); (2) Areas of research, sectors, and products that use BC (including research that did not use the kombucha drink, but used food waste as a source of carbon and nitrogen); and (3) Production, sustainability, and circular economy: perspectives, challenges, and trends in the use of BC (including some advantages and disadvantages of BC production through the kombucha drink).

Metagenomic and physicochemical analysis of Kombucha beverage produced from tea waste

Kombucha beverage produced through fermentation of sugared tea using bacteria and yeast has gained attention for its beneficial health benefits. However, the cost linked to the raw materials often increases the upstream process expenses, thereby the overall operating expenditures. Thus, there is a need to explore alternative waste and cost-effective raw materials for Kombucha fermentation. The present study, compared the physico-chemical and microbial growth pattern of Kombucha beverage production using tea waste from the tea processing industries with that of the green/black tea, reporting similar trends irrespective of its type. Further, the amplicon sequencing of 16S rRNA showed dominant presence of Komagataeibacter rhaeticus and high throughput sequencing of ITS1 confirmed the presence of yeast species similar to Brettanomyces bruxellensis in the tea waste based Kombucha beverage. Appreciable amount of carbohydrates (8.5/100 g) and energy (34 kcal/100 g) with appropriate organoleptic properties favourable for human consumption were also observed during the nutritional content and qualitative property assessment. The overall study showed a broad taxonomic and functional diversity existing during Kombucha fermentation process with tea waste to maintain a sustained eco-system to facilitate cost-effective beverage production with desired properties for safe consumption.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05476-3.

A look into Phaffia rhodozyma biorefinery: From the recovery and fractionation of carotenoids, lipids and proteins to the sustainable manufacturing of biologically active bioplastics

Carotenoids over-producing yeast has become a focus of interest of the biorefineries, in which the integration of the bioproduction with the following downstream processing units for the recovery and purification of carotenoids and other value-added byproducts is crucial to improve the sustainability and profitability of the overall bioprocess. Aiming the future implementation of Phaffia rhodozyma-based biorefineries, in this work, an integrative process for fractionation of intracellular compounds from P. rhodozyma biomass using non-hazardous bio-based solvents was developed. After one-extraction step, the total amount of astaxanthin, β-carotene, lipids and proteins recovered was 63.11 µg/g_DCW, 42.81 µg/g_DCW, 53.75 mg/g_DCW and 10.93 mg/g, respectively. The implementation of sequential back-extraction processes and integration with saponification and precipitation operations allowed the efficient fractionation and recovery (% w/w) of astaxanthin (∼72.5 %), β-carotene ∼90.17 %), proteins (21.04 %) and lipids (23.72 %). After fractionation, the manufacture of carotenoids-based products was demonstrated, through the mixture of carotenoids-rich extracts with bacterial cellulose to obtain biologically active bioplastics.

Reconstruction of Simplified Microbial Consortia to Modulate Sensory Quality of Kombucha Tea

Kombucha is a fermented tea with a long history of production and consumption. It has been gaining popularity thanks to its refreshing taste and assumed beneficial properties. The microbial community responsible for tea fermentation—acetic acid bacteria (AAB), yeasts, and lactic acid bacteria (LAB)—is mainly found embedded in an extracellular cellulosic matrix located at the liquid–air interphase. To optimize the production process and investigate the contribution of individual strains, a collection of 26 unique strains was established from an artisanal-scale kombucha production; it included 13 AAB, 12 yeasts, and one LAB. Among these, distinctive strains, namely Novacetimonas hansenii T7SS-4G1, Brettanomyces bruxellensis T7SB-5W6, and Zygosaccharomyces parabailii T7SS-4W1, were used in mono- and co-culture fermentations. The monocultures highlighted important species-specific differences in the metabolism of sugars and organic acids, while binary co-cultures demonstrated the roles played by bacteria and yeasts in the production of cellulose and typical volatile acidity. Aroma complexity and sensory perception were comparable between reconstructed (with the three strains) and native microbial consortia. This study provided a broad picture of the strains’ metabolic signatures, facilitating the standardization of kombucha production in order to obtain a product with desired characteristics by modulating strains presence or abundance.

Cost-Effective Synthesis of Bacterial Cellulose and Its Applications in the Food and Environmental Sectors

Bacterial cellulose (BC), also termed bio-cellulose, has been recognized as a biomaterial of vital importance, thanks to its impressive structural features, diverse synthesis routes, high thermomechanical properties, and its ability to combine with multiple additives to form composites for a wide range of applications in diversified areas. Its purity, nontoxicity, and better physico-mechanical features than plant cellulose (PC) make it a better choice for biological applications. However, a major issue with the use of BC instead of PC for various applications is its high production costs, mainly caused by the use of expensive components in the chemically defined media, such as Hestrin-Schramm (HS) medium. Furthermore, the low yield of BC-producing bacteria indirectly accounts for the high cost of BC-based products. Over the last couple of decades, extensive efforts have been devoted to the exploration of low-cost carbon sources for BC production, besides identifying efficient bacterial strains as well as developing engineered strains, developing advanced reactors, and optimizing the culturing conditions for the high yield and productivity of BC, with the aim to minimize its production cost. Considering the applications, BC has attracted attention in highly diversified areas, such as medical, pharmaceutics, textile, cosmetics, food, environmental, and industrial sectors. This review is focused on overviewing the cost-effective synthesis routes for BC production, along with its noteworthy applications in the food and environmental sectors. We have made a comprehensive review of recent papers regarding the cost-effective production and applications of BC in the food and environmental sectors. This review provides the basic knowledge and understanding for cost-effective and scaleup of BC production by discussing the techno-economic analysis of BC production, BC market, and commercialization of BC products. It explores BC applications as food additives as its functionalization to minimize different environmental hazards, such as air contaminants and water pollutants.

Potential use of olive oil mill wastewater for bacterial cellulose production

In this study, olive oil mill wastewater (OOMW), an important waste in the Mediterranean basin, was evaluated to produce bacterial cellulose (BC). For this purpose, the effects of different ratios of OOMW fractions (25–100%) and some additional nutrients (yeast extract, peptone and Hestrin-Schramm medium (HS) components) on BC productions were investigated. Unsupplemented OOMW medium (75% and 100%) yielded as much as BC obtained in HS medium (0.65 g/L), while enrichment of OOMW medium (%100) with yeast extract (5 g/L) and peptone (5 g/L) increased the amount of BC by 5.5 times, reaching to 5.33 g/L. In addition, produced BCs were characterized by FT-IR, TGA, XRD and SEM analyses. BC from OOMW medium (100% OOMW with supplementation) has a high thermal decomposition temperature (316.8°C), whereas it has lower crystallinity index (57%). According to the FT-IR analysis, it was observed that the components of OOMW might be absorbed by BCs. Thus, higher yield productions of BCs from OOMW media compared to BC obtained from HS medium indicate that olive oil industry wastes can be integrated into BC production for industrial applications.