Partial purification, characterization of Lactobacillus sp. G5 lipase and their probiotic potential

Lipase from Lactobacillus sp G5 isolate was partially purified and characterized. Out of 22 isolates, only seven (G1-G7) were phenotypically and biochemically characterized as Lactobacillus. However, only G5 isolate showed highest enzyme activity of 31.27 U/ml and chosen for partial purification and characterization. After ammonium sulphate precipitation and dialysis, specific activity of the enzyme was found to be 0.770 IU. During optimization, the enzyme showed maximum activity at pH 8/40°C. Stability was found at pH range 7-9, with temperature range 30°C-60°C. The enzyme showed maximum activity at a pNPA concentration of 0.150 mg/1.5 ml/1 ml enzyme solution. Vmax and Km values were 27.32 U/ml and 0.04 mg/min. Among several substrates tested (tween-20, olive oil, castor oil, palm oil, glycerol tributyrate and ghee), maximum affinity was observed towards glycerol tributyrate. Further, the G5 isolate showed good number of probiotic qualities viz., tolerated 1.5% bile salt for 4 h and at 2% the viability decreased, while luxuriant growth was observed at pH 3 and survived at pH 1 and 2 for 4 h. In addition, G5 exhibited resistance to lincomycin and was sensitive to chlorotetracyclin. The results obtained in the present study would indicate the stability of Lactobacillus G5 isolate in hydrolyzing lipids and probably a promising probiotic candidate.