ORIGINAL ARTICLES   

Minerva Biotecnologica 2012 September;24(3):83-9

Copyright © 2012 EDIZIONI MINERVA MEDICA

lingua: Inglese

A statistical approach for optimization of lipase production by using rice straw: analysis of different inducers and nitrogen sources effect

Khayati Gh. ¹, Kiyani F. ²

¹ Department of Chemical Engineering, Technical Faculty, Guilan University, Rasht, Iran; ² Department of Biology, Science and Research Branch, Islamic Azad University, Rasht, Iran

Aim. The main goal of this study was lipase production from indigenous wastes and survey on enzyme activity and stability.
Methods. A statistical approach was used for statistical optimization of lipase production from rice straw. The Plackett-Burman design was used in the first step to evaluate the effects of eight factors, including olive oil, rapeseed oil, palm oil, peanut oil as inducers and corn steep liquor, soybean meal, ammonium sulfate, urea as nitrogen sources. In the second step, the concentrations of olive oil and soybean meal were further optimized using central composite designs and response surface analysis.
Results. The optimized concentration of olive oil and soybean meal was 1.38 and 1.27 (%w/w) as inducer and nitrogen sources, respectively. Maximum lipase activity from the experimental was determined to be 58.76 (U/g substrate) under the optimal conditions. The most hydrolytic activity was obtained at pH and temperature 8 °C and 40 °C using pNPP as substrate, respectively.
Conclusion. The results showed that lipase activity influenced significantly by the concentration of olive oil as inducer and soybean meal as nitrogen source in the medium. The enzyme was stable in alkaline media (pH range from 7.0 to 10.0).