Journal of Pure and Applied MicrobiologyVol. 9 No. Special Edition May. 2015

Identification and Selection of Lactic Acid Bacteria Resistance to Acid and Bile Salt Isolated from Corn Silage

L. Li1, N. Zhang 2, L. Kong2, WC. Zhao2, Y.N. Xiao1, B.X. Li1* and X.R. Han1

1National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, College of Land and Environment, Shenyang Agricultural University, Shenyang, Liaoning 110866, China. 2College of Biological Science & Technology, Shenyang Agricultural University, Shenyang, Liaoning 110866, China.

Received on 27 January 2015 and accepted on 10 March 2015

 

ABSTRACT

The aim of the present study was to identification and selection of lactic acid bacteria resistance to acid and bile salt isolated from naturally fermented corn silage. Based on 16S rDNA gene sequence analysis, they were identified as Lactobacillus plantarum R1, Lactobacillus plantarum R2, Lactobacillus plantarum R3 and Weissella paramesenteroides ZH1. Growth curve, acid production rate, acid and bile salt tolerance of strains were determined. Isolates were cultured for 12h, and acid-production rate is significantly higher than other strains. In the silage fermentation process, isolates can be used as start strains. R1, R2, R3 have strong acid resistance, their relative OD600nm values were 53.06%, 55.14%, 57.90%, respectively. ZH1 have no acid resistance (6.33%). At 0.03% (w/v) concentration of bile salt for 16h, isolates R1, R2, R3, ZH1 were resistant to bile salt and maintained the high population level, their relative OD600nm values were 88.30%, 87.32%, 82.14%, 59.74%, respectively. At 0.06% (w/v) concentration of bile salt, the relative OD600nm values of isolates were 84.91%, 70.47%, 68.61%, 19.87%, respectively. The results show that R1, R2, R3 exhibited resistance to low pH and tolerance to high concentrations of bile salts, and they could be used as silage additives.

Keywords : lactic acid bacteria; acid and bile salt tolerance; 16S rDNA; silage.