Solid-state Fermentation Of Wheat Bran Research Articles

Production of cellulases and hemicellulases by Penicillium echinulatum grown on pretreated sugar cane bagasse and wheat bran in solid-state fermentation

To evaluate the solid-state fermentation (SSF) production of cellulase and hemicellulases (xylanases), by Penicillium echinulatum 9A02S1, in experiments carried out with different concentrations of the pretreated sugar cane bagasse (PSCB) and wheat bran (WB). This study reports the production of xylanolytic and cellulolytic enzymes by P. echinulatum 9A02S1 using a cheap medium containing PSCB and WB under SSF. The highest amounts of filter paper activity (FPA) could be measured on mixtures of PSCB and WB (32.89 +/- 1.90 U gdm(-1)). The highest beta-glucosidase activity was 58.95 +/- 2.58 U gdm(-1) on the fourth day. The highest activity for endoglucanases was 282.36 +/- 1.23 U gdm(-1) on the fourth day, and for xylanases the activity was around 10 U gdm(-1) from the second to the fourth day. The present work has established the potential of P. echinulatum for FPA, endoglucanase, beta-glucosidase and xylanase productions in SSF, indicating that WB may be partially substituted by PSCB. The incorporation of cheap sources, such as sugar cane bagasse, into media for the production of lignocellulose enzymes should help decrease the production costs of enzymatic complexes that can hydrolyse lignocellulose residues for the formation of fermented syrups, thus contributing to the economic production of bioethanol.

Optimisation of downstream processing parameters for the recovery of pectinase from the fermented bran of Aspergillus carbonarius

Aspergillus carbonarius produces extracellular pectinases when grown on wheat bran in solid-state fermentation (SSF) on a laboratory scale in flasks. The downstream processing parameters for recovery of the crude pectinases from the fermented bran were optimised. Optimum time and temperature of extraction were determined to be 15 min and 30°C. The enzyme could be concentrated at least 4-fold in the extract by sequential extractions. Extraction using water or acetate buffer (pH 4.3) containing sodium sulphate resulted in maximum enzyme recovery. Colour and polysaccharides in the enzyme extract could be minimised by treatment with sodium chloride and activated charcoal. Concentration of the enzyme by ultrafiltration resulted in a 50-fold concentration of activity with 91% recovery.

Clarification of xanthan gum with extracellular enzymes secreted by Trichoderma koningii

Xanthomonas campestris cells present in xanthan fermentation broth were lysed by enzymes secreted by Trichoderma koningii. Protease which appeared responsible for cell lysis was produced by the fungus in solid-state fermentation of wheat bran optimally at pH 7 and 30°C in 72 h. The culture filtrate, having protease in addition to other extracellular enzymes, was used as such to clarify xanthan solution and found to lyse the cells optimally at pH 7 and 50°C. The maximum transparency of xanthan solution achieved was 63%.

Solid-state fermentation of wheat bran by Trichoderma reesei QM9414: substrate composition changes, C balance, enzyme production, growth and kinetics

A description is given of the solid-state fermentation of wheat bran by Trichoderma reesei QM9414 at constant temperature and relative humidity. Glucosamine, the oxygen consumption rate (OCR), the carbon dioxide production rate (CPR), changes in wheat bran composition and the production of four enzymes were measured during 125 h of fermentation. A C balance was set up between CO2 production, based on CPR measurements, CO2 production as expected on the basis of substrate composition changes and substrate elemental composition in combination with dry-matter weight loss. Glucosamine was used as the measure of biomass. The results indicate that the glucosamine content of fungi in liquid culture cannot be used to estimate the biomass content in solid-state fermentations. Using glucosamine, correlations between fungal growth and respiration kinetics could only partly be described with the linear-growth model of Pirt. A decline in OCR and CPR started the moment the glucosamine level was 50% of its maximum value. After the glucosamine level had reached its maximum OCR and CPR continued to decline. The activities of xylanase and protease are linearly related to the glucosamine level. No clear correlations between glucosamine and carboxylmethylcellulose-hydrolysing enzyme activity and amylase activity were found.

Medium optimization for nuclease P1 production by Penicillium citrinum in solid-state fermentation using polyurethane foam as inert carrier

A solid-state fermentation system, using polyurethane foam as an inert carrier, was used for the production of nuclease P1 by Penicillium citrinum. Optimization of nuclease P1 production was carried out using a synthetic liquid medium. After a two-step medium optimization using a fractional factorial experimental design, nuclease P1 productivity and specific activity are greatly increased. Nuclease P1 productivity and specific activity are ninefold and fourfold higher, respectively, than in solid-state fermentation of wheat bran and 500-fold and 20-fold higher, respectively, than in submerged fermentation. Additional advantages of the solid-state fermentation process using inert carrier are discussed.

Improvements in solid-state fermentation for glucoamylase production

Solid-state fermentation of wheat bran by Aspergillus niger for glucoamylase production was studied. Whole dough containing spores, and wheat bran, was used as inoculum and a 5% (w/w) level was found optimum for enzyme production. Improved nutrients supplementation, addition of whole corn (yellow) flour and better process controls resulted in a 5–6-fold increase in enzyme yield over preliminary results from laboratory-flask experiments. The productivity was about 520–560 IU enzyme per gram dry substrate in 96 h. When scaled-up in tray fermenters, about 80% enzyme production was achieved in comparison to flask experiments, in 36 h.