Isolation, screening and characterization of lipase from bacterial isolates and its application in detergents and oily waste water degradation

摘要

The present study was conducted to explore industrial potential of bacterial lipase. Seven isolates were isolated from oil contaminated soil samples. Isolated lipolytic bacteria were grown on lipolytic specific media comprising 1% (w/v) mustard oil. Egg-yolk test was carried out to determine primary lipase activity. The crude enzyme extracts of two isolates SI1 and S17 showing maximum lipolytic activity were prepared and applied for further practical applications. In oil displacement test, the isolated strains displaced oil (engine oil, vegetable oil, mustard oil, olive oil and crude oil) and exhibited maximum zones of displacement. Lipase was stable in different detergents. Optimum pH was found to be 8.5 (SI1) and 8.0 (SI7). Optimum temperature for SI1 and SI7 was recorded to be 60?C and 40?C, respectively. Ca2 enhanced activity of lipase. The activities of SI1 and SI7 lipase was increased by Sodium dodecyl sulphate (5%) while Tween-80 and Tween-20 negatively affected enzyme activity. Oil Biodegradation activity of isolated lipolytic strains in synthetic and real wastewater was estimated as well as oily stains removal from cotton cloth pieces by crude enzyme extract was carried out. The strains exhibited high efficiency in degrading oily waste water making these strains important from industrial point of view for application in wastewater degradation. Enzyme extract of these isolates also exhibited excellent oily stains removal performance, proving their efficiency to be applied as detergent additives.