Production and transesterification activity of mycelium bound lipase from Rhizomucor miehei
M.Y.B. Liew ', H.M. Ghazali 1*, K. Long', O.M. Lai' and A.M. Yazid2
1Department of Biotechnology, 2Department of Food Technology, Faculty of Food Science and Biotechnology,
Universiti Putra Malaysia, UPM 43400 Serdang, Selangor, D.E., Malaysia
3Malaysian Agriculture Research and Development Institute, 43400 Serdang, Selangor, D.E., Malaysia
Received 3 April 2000 / Accepted I7 July 2000
Abstract.
The production of mycelium bound lipase (MBL) from Rhizomucor miehei in liquid culture medium was studied over a 5 day incubation period with varying glucose (0.1 to 1.0% w/v) and palm oil concentrations (0 to 5% w/v). Maximum dry mycelium weight and highest lipolytic activity were obtained after 3 days where the concentration of glucose in the medium was 0.1% (w/v) and oil concentration was at 1% (w/v). Increasing the glucose concentration (> 0.5% w/v) resulted in a significant (p>0.05) reduction in lipolytic activity. Addition of 0.5 5.0% (w/v) of oil resulted in a significantly higher lipolytic activity than culture without any added oil. The MBL was capable of transesterifying a mixture of palm stearin and palm kernel olein (1: 1) at 60oC. Appreciable levels of transesterification were demonstrated by MBL produced in culture medium [with 1 % (w/v) oil] containing 0.1% to 0.25% (w/v) of glucose. Higher glucose concentration of >0.5% (w/v) resulted in MBL with insufficient lipase activity to catalyze the transesterification reaction. On the other hand, addition of oil (0.5 to 5% w/v) to the culture medium containing 0. 1% (w/v) glucose produced MBL which demonstrated varying degree of transesterification.
Keywords: Mycelium bound, lipase, Rhizomucor miehei, culture condition
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