Production of Lactic Acid by a Local Isolate of Lactobacillus plantarum Using Cheap Starchy Material Hydrolysates

Abstract

Some cheap starchy materials like sorghum grains and wheat bran were degraded by crude glucoamylase of a local isolate of Mucor sp., then Lactic Acid (LA) was produced by a local isolate of L. plantarum using sorghum flour hydrolysate, sorghum starch hydrolysate, soluble starch hydrolysate, wheat bran hydrolysate and date syrup with 10% reducing sugars. The yield of LA increased to 37.2 g/100 reducing sugars by using sorghum flour hydrolysate as a basal medium supplemented with (0.6+0.6)% yeast extract+(NH₄)₂HPO₄ and 0.06% MgSO₄.7H₂O, reducing sugars was 5%. The fermentation temperature was 30°C/96 h. Results indicated that using hydrolysates mixtures of sorghum flour and wheat bran improved LA fermentation. The yield of LA was 92.5 g by using sorghum flour and 50% wheat bran. Paper chromatography indicated that LA was the unique organic acid in the fermented broth.