Hydrogen peroxide (H2O2) supply significantly improves xanthan gum production mediated by Xanthomonas campestris in vitro

The importance of acetate, pyruvate, and citrate feeding times in improving xanthan production by Xanthomonas citri

Xanthan gum is a microbial polysaccharide produced by Xanthomonas and widely used in various industries. To produce xanthan gum, the native Xanthomonas citri-386 was used in a cheese-whey-based culture medium. The culture conditions were investigated in batch experiments based on the response surface methodology to increase xanthan production and viscosity. Three independent variables in this study included feeding times of acetate, pyruvate, and citrate. The maximum xanthan gum production and viscosity within 120 h by X. citri-386 using Box-Behnken design were 25.7 g/l and 65 500 cP, respectively, with a 151% and 394% increase as compared to the control sample. Overall, the findings of this study recommend the use of X. citri-386 in the cheese-whey-based medium as an economical medium with optimal amounts of acetate, pyruvate, and citrate for commercial production of xanthan gum on an industrial scale. The adjustment of the pyruvate and acetate concentrations optimized xanthan gum production in the environment.

Production and application of xanthan gum-prospects in the dairy and plant-based milk food industry: a review

Xanthan gum (XG) is an important industrial microbial exopolysaccharide. It has found applications in various industries, such as pharmaceuticals, cosmetics, paints and coatings, and wastewater treatment, but especially in the food industry. The thickening and stabilizing properties of XG make it a valuable ingredient in many food products. This review presents a comprehensive overview of the various potential applications of this versatile ingredient in the food industry. Especially in the plant-based food industries due to current interest of consumers in cheaper protein sources and health purposes. However, challenges and opportunities also exist, and this review aims to identify and explore these issues in greater detail. Overall, this article represents a valuable contribution to the scientific understanding of XG and its potential applications in the food industry.

Biosynthesis of exopolysaccharide from waste molasses using Pantoea sp. BCCS 001 GH: a kinetic and optimization study

The bacterium Pantoea sp. BCCS 001 GH produces an exopolysaccharide (EPS) named Pantoan through using sugar beet molasses (SBM) as an inexpensive and widely available carbon source. This study aims to investigate the kinetics and optimization of the Pantoan biosynthesis using Pantoea sp. BCCS 001 GH in submerged culture. During kinetics studies, the logistic model and Luedeking-Piret equation are precisely fit with the obtained experimental data. The response surface methodology (RSM)-central composite design (CCD) method is applied to evaluate the effects of four factors (SBM, peptone, Na2HPO4, and Triton X-100) on the concentration of Pantoan in batch culture of Pantoea sp. BCCS 001 GH. The experimental and predicted maximum Pantoan production yields are found 9.9 ± 0.5 and 10.30 g/L, respectively, and the best prediction factor concentrations are achieved at 31.5 g/L SBM, 2.73 g/L peptone, 3 g/L Na2HPO4, and 0.32 g/L Triton X-100 after 48 h of submerged culture fermentation, at 30 °C. The functional groups and major monosaccharides (glucose and galactose) of a purified Pantoan are described and confirmed by 1HNMR and FTIR. The produced Pantoan is also characterized by thermogravimetric analysis and the rheological properties of the biopolymer are investigated. The present work guides the design and optimization of the Pantoea sp. BCCS 001 GH culture media, to be fine-tuned and applied to invaluable EPS, which can be applicable in food and biotechnology applications.

Transcription factor GlbHLH regulates hyphal growth, stress resistance, and polysaccharide biosynthesis in Ganoderma lucidum

Basic helix-loop-helix (bHLH) transcription factors (TFs) participate in many physiological and cellular processes in eukaryotes. However, their functions remain unclear in the macro basidiomycete Ganoderma lucidum (G. lucidum). In this study, a gene encoding bHLH TF, GlbHLH, was identified in G. lucidum. The knockdown of GlbHLH by RNA interference reduced hyphal growth, hyphal branching, and resistant to osmotic, oxidative, and cell wall stress. The content of cell wall components β-1,3 glucan and chitin and the expression of their synthesis genes were decreased in the GlbHLH knockdown strains. The knockdown of GlbHLH led to an increase of intracellular reactive oxygen species by decreasing the enzyme activity and gene expression of antioxidant enzymes. Furthermore, the production of intracellular polysaccharides and extracellular polysaccharides was greatly decreased in the GlbHLH mutants. These results suggested that GlbHLH is involved in hyphal growth, stress response, and polysaccharide biosynthesis in G. lucidum.

Effect of NaCl addition on the production of welan gum with the UV mutant of Sphingomonas sp

Because of its excellent stability, non-toxicity, biodegradability and unique rheology, welan gum can be widely used in various fields, such as petroleum, biomedicine and food products. In this study, a high-yield mutant strain FM01-S09 was screened through two rounds of UV mutagenesis. Remarkably, the production of welan gum could be further increased by adding 4 mM NaCl at 32 h fermentation, reaching 30.12 ± 0.25 g/L (28.66% higher than no adding), and the NaCl-WG solution had stronger structural, impact resistance, and temperature resistance than H₂O₂-WG and WG solutions. Furthermore, the mechanism by which NaCl promotes welan gum synthesis was also investigated. It was found that cell membrane characteristics, intracellular microenvironment makeup, and key enzyme gene expression levels were significantly altered in different fermentation stages. Therefore, the addition of NaCl could effectively promote the growth and fermentation performance of Sphingomonas sp., providing a novel strategy for cost-effective welan gum production.

Biosynthesis, structure and antioxidant activities of xanthan gum from Xanthomonas campestris with additional furfural

Lignocellulosic-like materials are potentially low-cost fermentation substrates, but their pretreatment brings about by-products. This work investigated the effects of furfural on xanthan gum (XG) production, and product quality was evaluated by structure, viscosity and antioxidant capacities. Xanthomonas campestris maintained steady polysaccharide yield (above 13 g·L^-1) with enhanced cell growth at low furfural concentrations (below 3.2 g·L^-1). The products were verified as XG by FT-IR, XRD, NMR and monosaccharide analysis. Moreover, they were found to have reduced acetyl, rising pyruvate and up-to-down glucuronic acid groups as increasing furfural concentration. Furthermore, XG product with 1 g·L^-1 furfural addition showed the best hydroxyl scavenging effects, though reducing powers presented no variation. It was demonstrated that furfural, the common hydrolysis by-product, was not necessarily an inhibitor for fermentation, and an appropriate amount of furfural was beneficial to XG production with steady yield and good quality.

Use of Chicken Feather Peptone and Sugar Beet Molasses as Low Cost Substrates for Xanthan Production by Xanthomonas campestris MO-03

Xanthan gum is one of the polysaccharides most commonly used in a broad range of industries (food, cosmetics, pharmaceutical, etc.). Agro-industrial by-products are being explored as alternative low-cost nutrients to produce xanthan gum by Xanthomonas campestris. In this study, for the production of xanthan gum, sugar beet molasses and chicken feather peptone (CFP) were used as carbon and nitrogen sources, respectively. X. campestris produced the highest level of xanthan gum (20.5 g/L) at 60 h of cultivation using sugar beet molasses (40 g/L total sugar) supplemented with CFP (4 g/L) at pH 7, 200 rpm, and 30 °C. The pyruvic acid content of the xanthan gums increased with increasing CFP concentration. Compared with commercial organic nitrogen sources (tryptone, bacto peptone, and yeast extract), the highest production of xanthan gum was obtained with CFP. Moreover, among the tested peptones, the highest pyruvic acid (3.2%, w/w) content was obtained from CFP. The usage of sugar beet molasses and CFP as substrates in industries would enable a cost-efficient commercial production. These results suggest that sugar beet molasses and CFP can be used as available low-cost substrates for xanthan gum production by X. campestris.

Valorisation of chicken feathers for xanthan gum production using Xanthomonas campestris MO-03

Xanthan gum is an important commercial polysaccharide produced by Xanthomonas species. In this study, xanthan production was investigated using a local isolate of Xanthomonas campestris MO-03 in medium containing various concentrations of chicken feather peptone (CFP) as an enhancer substrate. CFP was produced with a chemical process and its chemical composition was determined. The addition of CFP (1–8 g/l) increased the conversion of sugar to xanthan gum in comparison with the control medium, which did not contain additional supplements. The highest xanthan production (24.45 g/l) was found at the 6 g/l CFP containing control medium in 54 h. This value was 1.73 fold higher than that of control medium (14.12 g/l). Moreover, addition of CFP improved the composition of xanthan gum; the pyruvate content of xanthan was 3.86% (w/w), higher than that of the control (2.2%, w/w). The xanthan gum yield was also influenced by the type of organic nitrogen sources. As a conclusion, CFP was found to be a suitable substrate for xanthan gum production.

Effect of pretreatment on the enzymatic hydrolysis of kitchen waste for xanthan production

The study was carried out to gain insight into the effect of pretreatment on enzymatic hydrolysis of kitchen waste (KW) for xanthan fermentation. Herein, various pretreatments were applied and it was found that chemical pretreatment had positive effect on the following enzymatic or overall hydrolysis process. The highest reducing sugar concentration was obtained as 51.87g/L from 2% HCl (90°C) pretreated sample, while the Kjeldahl nitrogen (KDN) concentration was 7.79g/L. Kinetic study showed that first order kinetic model was suitable to describe the enzymatic hydrolysis process. The obtained kitchen waste hydrolysate (KWH) was successfully applied for xanthan fermentation. Xanthan concentration reached 4.09-6.46g/L when KWH with 2% HCl (90°C) pretreatment was applied as medium. In comparison, a xanthan concentration of 3.25-5.57g/L was obtained from KWH without pretreatment. Therefore, pretreatment of KW using diluted acid is favorable for the overall hydrolysis process and effective for xanthan fermentation.