Optimized culture conditions for bacterial cellulose production by Acetobacter senegalensis MA1

Abstract

Background: Cellulose, the most versatile biomolecule on earth, is available in large quantities from plants. However, cellulose in plants is accompanied by other polymers like hemicellulose, lignin, and pectin. On the other hand, pure cellulose can be produced by some microorganisms, with the most active producer being Acetobacter xylinum. A. senengalensis is a gram-negative, obligate aerobic, motile coccus, isolated from Mango fruits in Senegal, capable of utilizing a variety of sugars and produce cellulose. Besides, the production is also influenced by other culture conditions. Previously, we isolated and identified A. senengalensis MA1, and characterized the bacterial cellulose (BC) produced. Results: The maximum cellulose production by A. senengalensis MA1 was pre-optimized for different parameters like carbon, nitrogen, precursor, polymer additive, pH, temperature, inoculum concentration, and incubation time. Further, the pre-optimized parameters were pooled, and the best combination was analyzed by using Central Composite Design (CCD) of Response Surface Methodology (RSM). Maximum BC production was achieved with glycerol, yeast extract, and PEG 6000 as the best carbon and nitrogen sources, and polymer additive, respectively, at 4.5 pH and an incubation temperature of 33.5°C. Around 20% of inoculum concentration gave a high yield after 30 days of inoculation. The interactions between culture conditions optimized by CCD included alterations in the composition of the HS medium with 50 mL L − 1 of glycerol, 7.50 g L − 1 of yeast extract at pH 6.0 by incubating at a temperature of 33.5°C along with 7.76 g L − 1 of PEG 6000. This gave a BC yield of wet weight as 469.83 g L − 1. Conclusion: The optimized conditions of growth medium resulted in enhanced production of bacterial cellulose by A. senegalensis MA1, which is around 20 times higher than that produced using an unoptimized HS medium. Further, the cellulose produced can be used in food and pharmaceuticals, for producing high-quality paper, wound dressing material, and nanocomposite films for food packaging.

Potato Juice, a Starch Industry Waste, as a Cost-Effective Medium for the Biosynthesis of Bacterial Cellulose

“…This, in turn, results in a decrease in intracellular pH. As a result, a high concentration of gluconic acid can change the activity of metabolic pathways responsible for BC synthesis, reducing the yield [ 34 , 35 ]. In contrast, when the culture medium contains fructose, K. xylinus cells convert this monosaccharide to acetic acid, which results in a lower drop in pH, as compared with gluconic acid [ 36 ].…”

Preparation, Marriage Chemistry and Applications of Graphene Quantum Dots–Nanocellulose Composite: A Brief Review

“…These bacterial isolates can normally be obtained from rotten vegetables and fruits. Similar to plant-derived cellulose, some parameters or conditions, such as carbon source, nitrogen source, temperature, pH and agitation, are measured to produce a high yield of bacterial cellulose [68,69]. Bacterial nanocellulose is pure in nature and has a low cytotoxicity, high pore distribution and high hydrophilicity due to the presence of OH groups on its surface [70,71].…”

Preparation of Komagataeibacter xylinus Inoculum for Bacterial Cellulose Biosynthesis Using Magnetically Assisted External-Loop Airlift Bioreactor

“…It should be also mentioned that the quantity and quality of the inoculum have a significant impact on the quantity and quality of the final product [11][12][13]. The optimal inoculum size for BC production varies (1-30%) depending on the strain, medium composition, fermentation time and type of culture [4,16,48]. The larger inoculum size with active seed culture minimizes the length of adaptation (lag period) phase and facilitates the biomass concentration with a short fermentation time leading to higher production of exopolysaccharides such as BC [48].…”