Purification and biochemical characterization of an extracellular lipase produced by a new strain of Rhizopus sp.

Maria Gabriela Bello Koblitz,Gláucia Maria Pastore

doi:10.1590/s1413-70542006000300016

Maria Gabriela Bello Koblitz, Gláucia Maria Pastore

Open Access

https://doi.org/10.1590/s1413-70542006000300016

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Abstract

The present study had as a goal to purify and characterize the lipolytic fraction secreted by a strain of Rhizopus sp. Only 3 steps of purification were necessary to achieve SDS-PAGE homogeneity. One band with 37.5 KDa molecular mass and with 1446 U/mg specific activity was obtained. The purified fraction presented 2 lipase isoforms; both showed optimum activity at 50ºC, and were stable between 6.5 and 7.5 pH values and at temperatures below 50ºC and also kept their activity in hexane. The lipase was inactivated by Hg+2 and by n-bromosuccinimide and activated by Na+.

Highlights

Lipases are enzymes belonging to the group of serine hydrolases (E.C. 3.1.1.3)
Among the various industrial applications of lipases, two of them have special interest flavor ester synthesis for use in the food and pharmaceutical industries (MACEDO et al, 2004; MELLO et al, 2005) and the biodiesel production (PARK & PIZARRO, 2003). Besides their industrial application possibilities, the lipases are linked to the deterioration of some products, mainly dairy products and oils, and the identification and study of their mode of action may aid in the solution of these problems (HIOL et al, 2000)
Microorganism and Culture conditions mL of spore suspension, from a culture in PDA medium after 72 hours incubation, was inoculated into 500 mL Erlenmeyer flasks containing 20 g of wheat bran and water (60:40 w/w). These flasks were incubated at 30oC for 120 hours and the lipase produced was extracted with distilled water, followed by filtration

Summary

Introduction

Lipases are enzymes belonging to the group of serine hydrolases (E.C. 3.1.1.3) Their natural substrates are triglycerides and their mode of action is similar to that of the esterases. The lipases are able to catalyze hydrolysis, esterification, transesterification and lactonization (intramolecular esterification) (JAEGER & EGGERT, 2002) This flexibility, associated with the possibility of different substrate specificity among the different lipases, gives these enzymes an enormous potential for applications (GANDHI et al, 2000). Among the various industrial applications of lipases, two of them have special interest flavor ester synthesis for use in the food and pharmaceutical industries (MACEDO et al, 2004; MELLO et al, 2005) and the biodiesel production (PARK & PIZARRO, 2003) Besides their industrial application possibilities, the lipases are linked to the deterioration of some products, mainly dairy products and oils, and the identification and study of their mode of action may aid in the solution of these problems (HIOL et al, 2000)

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