Dilute acid pretreatment and enzymatic sachharification of cotton ginning waste

Abstract

The objective is to study the effect of dilute sulfuric acid pretreatment and enzymatic saccharification of cotton ginning waste to produced fermentable sugars. The Box Behnken design (BBD) was used for optimization of physical parameters. Method: Cellulase production by Trichoderma sp. (A11) was carried out under solid state fermentation using wheat bran. Pretreatment were carried out with 3% (V/V) diluted sulfuric acid and sachharification with crude cellulase enzyme of cotton ginning waste. The proximate analysis of treated and untreated cotton ginning biomass was done by Goering and Van Soest method to find the cellulose, hemicellulose and lignin content. The total reducing sugar was measured by using Di-nitro salicylic acid (DNSA) method. Incubation time, moisture ratio and substrate loading was optimized by using BBD for sachharification of cotton ginning waste. Finding: Untreated cotton ginning waste biomass contain 40.7% (w/w) of cellulose and 17.3 % (w/w) of lignin. Under sulfuric acid treatment, the residual acid treated cotton ginning waste biomass was found to have 62.4 4.1 % (w/w) cellulose and 9.9 0.6 % (w/w) lignin. Acid treated cotton ginning waste produced 117.3 mg/g while as untreated cotton ginning waste produced 29.7mg/g total reducing sugar. After statistical optimization by using BBD total reducing sugar was increased to 328 mg/g experimentally, at an optimum 5% of substrate concentration, 10 FPU enzyme loading on 7th day of incubation period and at 5 pH. Application: The fermentable sugar which is produced from cotton ginning waste biomass which can be further utilized for bioethanol production.