Screening of Lactic Acid Bacteria for Silage Inoculant Candidate

Abstract

Abstract Silage fermentation is generally assisted by lactic acid bacteria (LAB). The aim of this study was to screen selected LABs for silage inoculant. A total of 60 LAB isolates from the Indonesian Culture Collection (InaCC) were used in this study. Screening was carried out in an MRS broth medium using three different substrates, which were glucose, sucrose, and carboxyl methyl cellulose (CMC). The supernatant from LAB cultures was tested for pH, lactic acid (LA) concentration, antimicrobial activity, and cellulolytic activity. The results of the screening obtained 4 LAB isolates to be used as silage inoculant. Three LAB isolates selected from the glucose substrate were Lactobacillus fermentum InaCC-B1024, Lactobacillus plantarum InaCC-B1028, and L. brevis InaCC-B1052. Lactobacillus fermentum InaCC B1024 has a pH, LA concentration, cellulolytic activity, and percentage inhibition of 3.71, 318.931 mM, and 0.806 U/mL, > 95% antibacterial inhibition against B. subtilis, S. auerus, K. michiganensis, S. lloydii, and S. gallinarum, and <35% antifungal activity against M. ramosissimus, A. flavus, F. oxysporum, and P. griseofulvum, respectively. L. plantarum InaCC-B1028 has a pH, LA concentration, cellulolytic activity, and percentage activity of 3.61, 318.833 mM, 0.866 U/ml, > 95% antibacterial activity against B. subtilis, E. coli, M. luteus, S.auerus, K. michiganensis, S.lloydii, S. gallinarum, and < 40% antifungal activity against M. ramosissimus, A. flavus, F. oxysporum, and P. griseofulvum, respectively. L. brevis InaCC-B1052 has a pH, LA concentration, cellulolytic activity, and percentage activity of 3.67, 301.676 mM, no cellulolytic activity, > 95% antibacterial activity against E. coli, M. luteus, S. auerus, K. michiganensis, S. lloydii, S. gallinarum, and < 25% antifungal activity against M. ramosissimus and A. flavus, respectively. One LAB isolate selected from sucrose was L. kimchii InaCC-B982. Its pH, LA concentration, cellulolytic activity, and percentage activity were 3.77, 285.5 mM, 7.288 U/mL, > 95% antibacterial activity against E. coli, M. luteus, S. auerus, K. michiganensis, S. lloydii, S. gallinarum, and <15% antifungal activity against M. ramosissimus, A. flavus, F. oxysporum, and P. griseofulvum, respectively. Based on the results, the four LABs could be used as silage inoculant candidates.