Isolation and screening of lactic acid bacteria using soybean- residue fermentation for animal feed

Abstract

This study aims to isolate Lactobacillus sp. strains that are able to ferment soybean residue at normal temperature to produce probiotic-rich animal feed. Three Lactobacillus sp. strains are isolated from different samples at Hoa Khanh market in Đa Nang city. All isolated strains produce a large amount of Lactic Acid: 2,06 ± 0,96 mg / ml (L4 strain), 2,10 ± 0,52 mg / ml (L3 strain) and 2,03 ± 0,34 mg /ml (D1 strain), growing well at 35-40°C, at the high salt concentration of 5%, in the wide range of pH from 3,5 – 9,5 and strongly inhibiting the growth of Escherichia coli and Salmonella typhi. They can grow on soybean residue material and reduce pH to 3,23 ÷ 3,65 after 3 days with the acid lactic produced from D1 and L3 strains of 0,756mg/ml and 0,821mg/ml, respectively.