Production efficiency and properties of bacterial cellulose membranes in a novel grape pomace hydrolysate by Komagataeibacter melomenusus AV436T and Komagataeibacter xylinus LMG 1518

Enhanced bacterial cellulose production by Komagataeibacter species and Hibiscus sabdariffa herbal tea

This study proposed Hibiscus sabdariffa as a novel substrate for BC production with Komagataeibacter species and their consortia. K. intermedius is found as the most efficient producer (5.98 g/L BC, 3.56 × 10-2 g-1 h-1 productivity rate) following K. maltaceti (4.44 g/L BC, 2.64 × 10-2 g-1 h-1 productivity rate) and K. nataicola (3.67 g/L BC, 2.18 × 10-2 g-1 h-1 productivity rate). Whereas agitation increased BC production with K. nataicola (1.22-fold, 4.49 g/L BC), K. maltaceti (1.24-fold, 5.52 g/L BC) and K. intermedius (1.27-fold, 7.63 g/L BC), irregular shaped BC was obtained. This could be a novel result as Komagataeibacter consortia increased BC production by 1.17-2.01-fold compared to monocultures resulting as 8.11 g/L BC through the co-cultivation of K. maltaceti-K. intermedius. Maximum increase was found to be 1.75-fold (1.79-fold WHC), occurring with monoculture of K. maltaceti, while 1.94-fold (1.26-fold WHC) with K. maltaceti-K. intermedius consortium when H. sabdariffa-based media compared Hestrin-Schramm media. Based on these results, this could be a novel result as H. sabdariffa-based media may replace the use of HS media in BC production by means of a bioactive content-rich plant and obtaining 3-D ultrafine porous structure with high thermal resistant (∼460-500 °C) BC with mono and co-cultivation of Komagataeibacter species to be used in industrial area.

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.

Customized 16S-23S rDNA ITS Amplicon Metagenomics for Acetic Acid Bacteria Species Identification in Vinegars and Kombuchas

Acetic acid bacteria (AAB) are involved in food and beverage production bioprocesses, like those in vinegar and kombucha. They oxidize sugars and alcohols into various metabolites, resulting in the final products' pleasant taste and aroma. The 16S rDNA amplicon metagenomics using Illumina technology is usually used to follow the microbiological development of these processes. However, the 16S rRNA gene sequences among different species of AAB are very similar, thus not enabling a reliable identification down to the species level but only to the genus. In this study, we have constructed primers for amplifying half of the 16S-23S rRNA gene internal transcribed spacer (ITS) for library construction and further sequencing using Illumina technology. This approach was successfully used to estimate the relative abundance of AAB species in defined consortia. Further application of this method for the analysis of different vinegar and kombucha samples proves it suitable for assessing the relative abundance of AAB species when these bacteria represent a predominant part of a microbial community.

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.

Exploitation of microbial activities at low pH to enhance planetary health

Awareness is growing that human health cannot be considered in isolation but is inextricably woven with the health of the environment in which we live. It is, however, under-recognized that the sustainability of human activities strongly relies on preserving the equilibrium of the microbial communities living in/on/around us. Microbial metabolic activities are instrumental for production, functionalization, processing, and preservation of food. For circular economy, microbial metabolism would be exploited to produce building blocks for the chemical industry, to achieve effective crop protection, agri-food waste revalorization, or biofuel production, as well as in bioremediation and bioaugmentation of contaminated areas. Low pH is undoubtedly a key physical-chemical parameter that needs to be considered for exploiting the powerful microbial metabolic arsenal. Deviation from optimal pH conditions has profound effects on shaping the microbial communities responsible for carrying out essential processes. Furthermore, novel strategies to combat contaminations and infections by pathogens rely on microbial-derived acidic molecules that suppress/inhibit their growth. Herein, we present the state-of-the-art of the knowledge on the impact of acidic pH in many applied areas and how this knowledge can guide us to use the immense arsenal of microbial metabolic activities for their more impactful exploitation in a Planetary Health perspective.

Exploring the potential of bacterial cellulose paste as a fat replacer for low-fat plant-based hamburger patties

Plant-based hamburger patties (PHPs) with reduced fat content made using fat replacers will meet the consumption goals of individuals who consume meat alternative products for health. In this study, we developed a dual-alternative food model by analysing the applicability of bacterial cellulose paste (BCP) as a fat replacer and supplementing it in PHPs. BCPs were prepared with solid contents of (w/w; 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%) and compared and analyzed with three types of conventional vegetable [coconut oil, margarine, and shortening (SH)] and animal fats (beef tallow, butter, and lard) for various characteristics (appearance, dimensional stability, hardness level, and rheological properties). According to the results, BCP with a solid content of 3.0% (w/w) had the most similar characteristics to SH. Therefore, using SH as a control fat, PHPs in which 0%, 25%, 50%, 75%, and 100% (w/w) SH were replaced by 3.0% (w/w) BCP were prepared. Analysis of the appearance, instrumental color, diameter reduction, thickness, cooking loss, and texture profile of the PHPs, confirmed that replacement of 25%-50% (w/w) SH with 3.0% (w/w) BCP in the preparation of PHP resulted in i) redder color, ii) better dimensional stability, iii) lower cooking loss, and iv) higher chewiness of the final products. The results of the sensory evaluation showed that the PHPs, with 25%-50% (w/w) SH replaced with 3.0% (w/w) BCP, exhibited no significant differences (p < 0.05) in overall preference scores compared to the full-SH sample. In conclusion, this study demonstrated the potential of BCP as a fat substitute for the production of PHPs.

Production of Bacterial Exopolysaccharides: Xanthan and Bacterial Cellulose

Recently, degradable biopolymers have become increasingly important as potential environmentally friendly biomaterials, providing a wide range of applications in various fields. Bacterial exopolysaccharides (EPSs) are biomacromolecules, which due to their unique properties have found applications in biomedicine, foodstuff, textiles, cosmetics, petroleum, pharmaceuticals, nanoelectronics, and environmental remediation. One of the important commercial polysaccharides produced on an industrial scale is xanthan. In recent years, the range of its application has expanded significantly. Bacterial cellulose (BC) is another unique EPS with a rapidly increasing range of applications. Due to the great prospects for their practical application, the development of their highly efficient production remains an important task. The present review summarizes the strategies for the cost-effective production of such important biomacromolecules as xanthan and BC and demonstrates for the first time common approaches to their efficient production and to obtaining new functional materials for a wide range of applications, including wound healing, drug delivery, tissue engineering, environmental remediation, nanoelectronics, and 3D bioprinting. In the end, we discuss present limitations of xanthan and BC production and the line of future research.

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.