Abstract
In order to make full use of rice straw (RS) produced at large quantity in China and to reduce the production cost of L-lactic acid, attempts were made to utilize the hydrolysate of RS as sole carbon source and the lignocellulose as inert support for producing L-lactic acid using solid state fermentation (SSF). The pretreated rice straw was enzymatically hydro- lyzed by cellulase, and the hydrolyzate, containing reducing sugars supplemented with a minimum of (NH4)2SO4, MnSO4, and yeast extract, was used as moistening agent to impregnate 5g of RS, which was used as the inert support for SSF. Maximum L-lactic acid production of 3.467g per 5g of support was obtained at 37 oC, using Lactobacillus casei as inoculum, after 5 days of fermentation with optimized process parameters such as 72% moisture content, 4g per 5g support of reducing sugars, 2.5ml per 5g support of inoculum size, 3g per 5g support of CaCO3, and pH 6.5.Download PDF