Komagataeibacter intermedius V-05: An Acetic Acid Bacterium Isolated from Vinegar Industry, with High Capacity for Bacterial Cellulose Production in Soybean Molasses Medium.

RESEARCH BACKGROUND: Despite the great properties of bacterial cellulose, its manufacture is still limited due to difficulties in large-scale production. These problems are mainly related to low production yields and high overall costs of the conventional culture media normally used. To surpass these problems, it is necessary to identify new cheap and sustainable carbon sources. Thus, this work aims to isolate and select a high cellulose-producing Komagataeibacter strain from vinegar industry, and study its potential for bacterial cellulose synthesis in an industrial soybean co-product, known as soybean molasses, used as fermentation medium. EXPERIMENTAL APPROACH: One isolated strain was able to produce high amount of cellulose in the standard Hestrin-Schramm medium, so we tested its ability to produce this biopolymer in a soybean molasses medium. The characteristics and properties of the produced bacterial cellulose membranes were analyzed by thermogravimetric analysis, X-ray diffraction, infrared spectroscopy, water-holding capacity and rehydration ratio. Genetic analysis of the selected strain served to determine its genus and species. RESULTS AND CONCLUSIONS: An isolated strain that produced the highest amount of cellulose in Hestrin-Schramm medium (3.7 g/L) was genetically identified as Komagataeibacter intermedius V-05. This strain produced 10.0 g/L of cellulose in soybean molasses medium. Membranes from both substrates had similar chemical structure, crystallinity and thermal degradation. Soybean molasses proved to be a suitable alternative medium for biosynthesis of cellulose in comparison with the standard medium. In addition to providing higher production yield, the membranes showed great structural characteristics, similar to those obtained from standard medium. NOVELTY AND SCIENTIFIC CONTRIBUTION: In this research, we have isolated and identified a Komagataeibacter strain which exhibits a high capacity for cellulose production in soybean molasses. The isolation and selection of strains with high capacity for microbial metabolite production is important for decreasing bioprocess costs. Furthermore, as there is a necessity today to find cheaper carbon sources to obtain microbial products at a lower cost, soybean molasses represents an interesting alternative medium to produce bacterial cellulose for its industrial application.

Rhamnolipid production by Pseudomonas aeruginosa grown on membranes of bacterial cellulose supplemented with corn bran water extract.

Surfactants represent a billionaire market of amphiphilic molecules with worldwide applications in almost every branch of modern industry. The most common surfactants, available and currently used, are chemically produced. However, there is an urge to replace these chemical compounds with those obtained by mild and green technologies such as microbial biosurfactants produced by fermentative processes. Rhamnolipids are glycolipid biosurfactants that present highly effective surface-active properties and enormous market potential; nevertheless, their production costs remain not competitive. Here, we present a process of rhamnolipid production by static submerged cultivation using membranes of bacterial cellulose as substrate. The mixture of the rhamnolipid congeners was characterized showing effective surface-active properties and high amount of di-rhamnolipids (95.6%). Through this fermentative technology, 15.8 g/L of rhamnolipid was reach using a very simple and low-cost medium. The present process might decrease biosurfactant production cost, avoid foam formation, and finally make rhamnolipid production more viable.

Production and characterization of bacterial cellulose membranes with hyaluronic acid from chicken comb.

The bacterial cellulose (BC), from Gluconacetobacter hansenii, is a biofilm with a high degree of crystallinity that can be used for therapeutic purposes and as a candidate for healing wounds. Hyaluronic acid (HA) is a constitutive polysaccharide found in the extracellular matrix and is a material used in tissue engineering and scaffolding for tissue regeneration. In this study, polymeric composites were produced in presence of hyaluronic acid isolated from chicken comb on different days of fermentation, specifically on the first (BCHA-SABT0) and third day (BCHA-SABT3) of fermentation. The structural characteristics, thermal stability and molar mass of hyaluronic acid from chicken comb were evaluated. Native membrane and polymeric composites were characterized with respect to their morphology and crystallinity. The optimized process of extraction and purification of hyaluronic acid resulted in low molar mass hyaluronic acid with structural characteristics similar to the standard commercial hyaluronic acid. The results demonstrate that the polymeric composites (BC/HA-SAB) can be produced in situ. The membranes produced on the third day presented better incorporation of HA-SAB between cellulose microfiber, resulting in membranes with higher thermal stability, higher roughness and lower crystallinity. The biocompatiblily of bacterial cellulose and the importance of hyaluronic acid as a component of extracellular matrix qualify the polymeric composites as promising biomaterials for tissue engineering.