Characterization of nanocellulose production by strains of Komagataeibacter sp. isolated from organic waste and Kombucha

Bacterial valorization of agricultural-waste into a nano-sized cellulosic matrix for mitigating emerging pharmaceutical pollutants: An eco-benign approach

For Bacterial Nanocellulose (BNC) production, standard methods are well-established, but there is a pressing need to explore cost-effective alternatives for BNC commercialization. This study investigates the feasibility of using syrup prepared from maize stalk as a valuable nutrient and sustainable carbon source for BNC production. Our study achieved a remarkable BNC production yield of 19.457 g L-1 by utilizing Komagataeibacter saccharivorans NUWB1 in combination with components from the Hestrin-Schramm (HS) medium. Physicochemical properties revealed that the obtained BNC exhibited a crystallinity index of 60.5 %, tensile strength of 43.5 MPa along with enhanced thermostability reaching up to 360 °C. N2 adsorption-desorption isotherm of the BNC displayed characteristics of type IV, indicating the presence of a mesoporous structure. The produced BNC underwent thorough investigation, focusing on its efficacy in addressing environmental concerns, particularly in removing emerging pharmaceutical pollutants like Metformin and Paracetamol. Remarkably, the BNC exhibited strong adsorption capabilities, aligning with the Langmuir isotherm and pseudo-second-order model. Thermodynamic analysis confirmed a spontaneous and endothermic adsorption process. Furthermore, the BNC showed potential for regeneration, enabling up to five recycling cycles. Cytotoxicity and oxidative stress assays validated the biocompatibility of BNC. Lastly, the BNC films displayed an impressive 88.73 % biodegradation within 21 days.

Bacterial cellulose biosynthesis: Optimization strategy using iranian nabat industry waste

Bacterial cellulose (BC) is a biopolymer has found extensive applications across different fields due to its nanostructure and biomaterial performance. This study focused on optimizing yield of BC produced by Komagataeibacter xylinus CH1, isolated from kombucha SCOBY. The study aimed to use Nabat industry waste (NIW) as a cost-effective alternative carbon source for submerged fermentation. To optimize the fermentation criteria, the central composite design was used with the inoculation amount (1.5-4.5 % VV-1), NIW (0-1%), and fermentation time (3-7 days) as independent variables. The impressive results indicated the yield was enhanced up to 45.543 gL-1 at 3.013 % VV-1 of inoculation, 0.516 % NIW, and 7 days of stirred fermentation. SEM, XRD, FTIR, and TGA were applied to evaluate the characteristics of freeze-dried BC, such as the three-dimensional, porous structure, crystalline peaks, amorphous haloes, and thermal stability. The physicochemical properties of BC including high moisture content (93.022 ± 0.472 %), water absorption rate (569.473 ± 3.739 %), water-holding capacity (1333.016 ± 3.680 %), porosity (166.247 ± 2.055 %), and low water activity (0.296 ± 0.030 %) were achieved. Rheological properties of BC suspensions showed that G' dominated over G″, with tan δ values lower than 1. These characteristics indicate NIW and stirred fermentation conditions are a promising method for producing BC in high yield.

Preparation of bacterial cellulose-based antibacterial membranes with prolonged release of drugs: Emphasis on the chemical structure of drugs

Bacterial cellulose (BC) based antibacterial membranes were synthesized, including BC-cefoperazone (BC-CEF) and BC-cefoperazone sodium (BC-CEF/Na). To examine the various drug loading processes, the structure, morphology, and physical-chemical characteristics of membranes were evaluated. Results demonstrated that both types of medicines were successfully absorbed into membranes, and membranes displayed identical morphology and FT-IR peaks. BC-CEF showed lower crystalline of XRD, which was likely caused by the combination of carboxyl and hydroxyl. However, there were no drug peaks seen in the membranes, indicating no alteration of ribbon crystallization of BC. Two types of antibacterial membranes have significantly distinct drug-loading traits and drug-releasing profiles. The drug loading rate of CEF (46.4 mg/g) was significantly greater than CEF/Na (30.3 mg/g). The cumulative drug-releasing profiles showed that only BC-CEF continues to release drugs for a lengthy period up to 48 h and exhibited good antimicrobial activity against S. aureus and E. coli until 48 h. The cytotoxicity assay demonstrated the great biocompatibility of all membranes. Findings indicated that BC-CEF has the potential use as a prolonged biocide in the biomedical. The idea that BC membranes can naturally incorporate the carboxyl groups from antibiotics is also innovative and can be useful in developing of drug delivery systems.

Eco-benign synthesis of nano‑gold chitosan-bacterial cellulose in spent ground coffee kombucha consortium: Characterization, microbiome community, and biological performance

Biomaterials that are mediocre for cell adhesion have been a concern for medical purposes. In this study, we fabricated nano‑gold chitosan-bacterial cellulose (CBC-Au) via a facile in-situ method using spent ground coffee (SGC) in a kombucha consortium. The eco-benign synthesis of monodispersed gold nanoparticles (Au NPs) in modified bacterial cellulose (BC) was successfully achieved in the presence of chitosan (CHI) and a symbiotic culture of bacteria and yeast (SCOBY). The dominant microbiome community in SGC kombucha were Lactobacillaceae and Saccharomycetes. Chitosan-bacterial cellulose (CBC) and CBC-Au affected the microfibril networks in the nano cellulose structures and decreased the porosity. The modified BC maintained its crystallinity up to 80 % after incorporating CHI and Au NPs. Depth profiling using X-ray photoelectron spectroscopy (XPS) indicated that the Au NPs were distributed in the deeper layers of the scaffolds and a limited amount on the surface of the scaffold. Aspergillus niger fungal strains validated the biodegradability of each scaffold as a decomposer. Bacteriostatically CBC-Au showed better antimicrobial activity than BC, in line with the adhesion of NIH-3T3 fibroblast cells and red blood cells (RBCs), which displayed good biocompatibility performance, indicating its potential use as a medical scaffold.

Microbiological and Physico-Chemical Characteristics of Black Tea Kombucha Fermented with a New Zealand Starter Culture

Kombucha is a popular sparkling sugared tea, fermented by a symbiotic culture of acetic acid bacteria (AAB) and yeast. The demand for kombucha continues to increase worldwide, mainly due to its perceived health benefits and appealing sensory properties. This study isolated and characterised the dominant AAB and yeast from a starter culture and kombucha broth after 0, 1, 3, 5, 7, 9, 11, and 14 days of fermentation at ambient temperature (22 °C). Yeast and AAB were isolated from the Kombucha samples using glucose yeast extract mannitol ethanol acetic acid (GYMEA) and yeast extract glucose chloramphenicol (YGC) media, respectively. The phenotypic and taxonomic identification of AAB and yeast were determined by morphological and biochemical characterisation, followed by a sequence analysis of the ribosomal RNA gene (16S rRNA for AAB and ITS for yeast). The changes in the microbial composition were associated with variations in the physico-chemical characteristics of kombucha tea, such as pH, titratable acidity, and total soluble solids (TSS). During fermentation, the acidity increased and the TSS decreased. The yield, moisture content, and water activity of the cellulosic pellicles which had developed at the end of fermentation were attributed to the presence of AAB. The dominant AAB species in the cellulosic pellicles and kombucha broth were identified as Komagataeibacter rhaeticus. The yeast isolates belonged to Debaryomyces prosopidis and Zygosaccharomyces lentus.

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).

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.

Diversity Analysis of Bacterial and Function Prediction in Hurunge From Mongolia

With the continuous infiltration of industrialization and modern lifestyle into pastoral areas, the types and processing capacity of Hurunge are decreasing, and the beneficial microbial resources contained in it are gradually disappearing. The preservation and processing of Hurunge are very important for herdsmen to successfully produce high-quality koumiss in the second year. Therefore, in this study, 12 precious Hurunge samples collected from Bulgan Province, Ovorkhangay Province, Arkhangay Province, and Tov Province of Mongolia were sequenced based on the V3-V4 region of the 16S rRNA gene, and the bacterial diversity and function were predicted and analyzed. There were significant differences in the species and abundance of bacteria in Hurunge from different regions and different production methods (p < 0.05). Compared with the traditional fermentation methods, the OTU level of Hurunge fermented in the capsule was low, the Acetobacter content was high and the bacterial diversity was low. Firmicutes and Lactobacillus were the dominant phylum and genus of 12 samples, respectively. The sample QHA contained Komagataeibacter with the potential ability to produce bacterial nanocellulose, and the abundance of Lactococcus in the Tov Province (Z) was significantly higher than that in the other three regions. Functional prediction analysis showed that genes related to the metabolism of bacterial growth and reproduction, especially carbohydrate and amino acid metabolism, played a dominant role in microorganisms. In summary, it is of great significance to further explore the bacterial diversity of Hurunge for the future development and research of beneficial microbial resources, promotion, and protection of the traditional ethnic dairy products.

Influence of cellulose nanocrystal addition on the production and characterization of bacterial nanocellulose

Bacterial nanocellulose (BNC) is characterized by high purity and excellent mechanical properties; however, its production is constrained by low yield. Therefore, efforts aimed at improving its yield and material properties are imperative. This study investigated the effect of adding different concentrations (0%, 0.5%, and 1.0%) of cellulose nanocrystal (CNC) in Hestrin-Schramm modified medium on the yield and properties of BNC produced by Komagataeibacter sp. SFCB22-18. The BNC yield increased as following an increase in added CNC concentration. Also, the morphology, structure, crystallinity, thermal stability, and mechanical properties of BNC improved after CNC incorporation. A low CNC concentration (0.1%) favored mechanical strength, whereas 0.5% gave the optimum morphology, structural, and thermal stability. These results showed that modifying BNC with CNC could help increase yield and improve its properties, and thus; the potentiality of BNC in various applications would be much enhanced.