Production and optimization of xylooligosaccharides from corncob by Bacillus aerophilus KGJ2 xylanase and its antioxidant potential.

The aim of the present study is to produce xylooligosaccharides (XOS) from corncob xylan. The xylan was extracted from corncob using methods like dilute acid, dilute alkali and sodium hypochlorite treatment. Corncob xylan extracted using alkali was characterized by FT-IR and TG-DSC. The extracted xylan was subjected to enzymatic hydrolysis using Bacillus aerophilus KGJ2 xylanase for XOS production. To increase the yield of XOS, the effects of various process parameters like substrate concentration, reaction time, and enzyme concentration on XOS production were investigated. XOS prepared was characterized by HPTLC. Anti oxidant potential of produced XOS was evaluated and the DPPH assay showed that XOS possessed concentration dependent free radical scavenging activity.

Xanthan from sulphuric acid treated tapioca pulp: influence of acid concentration on xanthan fermentation.

Xanthan gum was produced by fermentation of sulphuric acid pre-treated tapioca pulp. Effect of sulphuric acid concentration (0.5%, 2.5% and 5.0%) on xanthan fermentation was investigated. Maximum xanthan yield (7.1g/l) was obtained with 0.5% sulphuric acid pre-treatment. Further, increase in sulphuric acid concentration caused formation of inhibitory substance and lowered xanthan yield. The product was confirmed as xanthan using FTIR, (1)H NMR analyses. Viscosity was measured by Brookfield viscometer and the molecular weight was determined from the intrinsic viscosity. The results confirmed that the yield and quality of xanthan produced were strongly influenced by the acid concentration.

Statistical optimization of pullulan production from Asian palm kernel and evaluation of its properties.

Pullulan, a biodegradable exopolysaccharide, was produced from Asian Palmyra palm kernel by solid-state fermentation. Levels of medium variables, namely carbon to nitrogen ratio (C/N), pH, NaCl concentration and ZnSO4·5H2O concentration were optimized to maximize pullulan production using Box-Behnken design of experiments. Optimal values were predicted as: C/N ratio - 28.1, pH - 6.6, NaCl - 0.78 g/l and ZnSO4·5H2O - 0.37 g/l. Theoretical pullulan yield predicted under optimum condition was 30.4 mg/gds. Pullulan was produced under optimum condition and an experimental yield of 28.7 ± 0.3mg/gds was obtained. (13)C NMR spectra of the exopolysaccharide produced from Asian palm kernel revealed the presence of anomeric α (1→6) linked maltosyl units. The weight-average molecular weight of the polymer was determined to be 8.4×10(6)Da by gel permeation chromatography. Thermal decomposition temperature of pullulan was obtained to be 245°C. The tensile strength of pullulan film (0.5mm thick) was found to be 27 MPa.

Xylanase production from Bacillus aerophilus KGJ2 and its application in xylooligosaccharides preparation.

Xylanolytic enzyme was produced using a newly isolated Bacillus aerophilus KGJ2 and low cost lignocellulosic sources in solid state fermentation. Seven different agricultural residues (wheat bran, tea dust, saw dust, paper waste, cassava bagasse, rice straw and rice husk) and six nitrogen source namely yeast extract, beef extract, peptone, ammonium nitrate, ammonium sulphate, and ammonium chloride were examined for xylanase production. Upon initial screening, wheat bran and ammonium chloride were chosen as suitable carbon source and nitrogen source respectively. Plackett-Burman fractional factorial design was employed to screen the important process variables affecting enzyme production. Substrate concentration, nitrogen source, moisture content and MgSO4·7H2O were identified as statistically significant variables. Subsequently Box-Behnken method was used to optimize the process conditions to achieve maximum xylanase yield. Under optimized conditions xylanase yield was 45.9 U/gds. Best xylanase activity was obtained at 70 °C and pH 4.0. It retained more than 90% activity after incubation at 80-90 °C for 60 min. The hydrolytic efficiency of xylanase on xylan was examined and xylobiose, xylotriose and xylotetrose were obtained as hydrolytic products.

Production of pullulan by Aureobasidium pullulans from Asian palm kernel: a novel substrate.

Production of a commercially important biodegradable polymer, pullulan, by Aureobasidium pullulans from four agricultural wastes namely wheat bran, rice bran, coconut kernel and palm kernel was evaluated in solid state fermentation. Under the experimental conditions, palm kernel resulted in highest concentration of pullulan (16 g/L) among the four solid substrates. Optimum initial pH and moisture content for pullulan production were found out to be 6.5 and 50% respectively. 18.43 g/L of pullulan was produced from Asian palm kernel with initial pH 6.5 after 7 days of fermentation and yeast like morphology was predominant under this condition. Among different nitrogen sources tried in this study, yeast extract was found to the best. The pullulan produced from palm kernel was characterized by FTIR and (1)H NMR. The results were matching with that of commercial pullulan. Thus, Asian palm kernel appears to be an attractive low cost carbon source for the production of pullulan.