In Vitro Evaluation of Potential Probiotic StrainLactococcus lactisGh1 and Its Bacteriocin-Like Inhibitory Substances for Potential Use in the Food Industry

Determination of a microbial strain for the joining into sustenance items requires both in vitro and in vivo assessment. A newly isolated bacteriocin-like inhibitory substance (BLIS) producing lactic acid bacterium,Lactococcus lactisGh1, was isolated from a traditional flavour enhancer and evaluated in vitro for its potential applications in the food industry. Results from this study showed thatL. lactiswas tolerant to NaCl (<= 4.0%, w/v), phenol (<= 0.4%, w/v), 0.3% (w/v) bile salt, and pH 3. BLIS fromL. lactisshowed antimicrobial activity againstListeria monocytogenesATCC 15313 and was susceptible to 10 types of antibiotics. The absence of haemolytic activity and the presence of acid phosphatase and naphthol-AS-BI-phosphohydrolase were observed inL. lactis.L. lactiscould coagulate milk and showed a negative response to amylolytic and proteolytic activities and did not secrete beta-galactosidase. The antimicrobial activity of BLIS was completely abolished at 121 degrees C. The BLIS was conserved at 4 degrees C in BHI and MRS medium up to 6-4 months, respectively. BLIS activity was more stable in BHI as compared to MRS after four freeze-thaw cycles and was not affected by a wide range of pH (pH 4-8). BLIS was sensitive to proteinase k and resistant to catalase and trypsin. The antimicrobial activity was slightly reduced by acetone, ethanol, methanol, and acetonitrile at 10% (v/v) and also towards Tween-80, urea, and NaCl 1% (v/v). Results from this study have demonstrated thatL. lactishas a vast potential to be applied in the food industry, such as for the preparation of starter culture, functional foods, and probiotic products.

Automated summary

The study demonstrated that a newly isolated bacteriocin-producing Lactococcus lactis strain has the potential to be applied in the food industry for various purposes, such as starter culture preparation, functional foods, and probiotic products.