Endophytic Fungi Associated with Mediterranean Plants as a Source of Mycelium-Bound Lipases

Abstract

A screening of endophytic fungi isolated from Mediterranean plants rendered a mycelium-bound lipase from a strain of Rhizopus oryzae that catalyzed the esterification of fatty acids in isooctane. The influence of various factors (water content, temperature, and pH) on ester synthesis was investigated. Catalytic activity was inversely correlated with water content. This enzyme was active over the entire pH range studied, from pH 3 to pH 8, and activity was maximal at pH 4 and pH 7. The enzyme was thermostable, with maximal activity at 60 degrees C.

Potential application in biocatalysis of mycelium-bound lipases from Amazonian fungi

“…The preliminary lipolytic screening was carried out according to the methodology described by Torres et al 23 with modifications. The medium used was composed of mycological peptone (5.0 g L -1 ), yeast extract (3.0 g L -1 ), agar (10.0 g L -1 ), and tributyrine (Sigma) added to give a final concentration of 0.1% (v/v).…”

“…23,26,29,32 The initial selection for the detection of a particular activity has a significant weighting in the screening process, since it aims to eliminate the worst candidates and, in general, is carried out through the cultivation of microorganisms in a solid culture medium, in Petri dishes. 44 Triacylglycerides such as triolein or -butyrin are used as standard substrates for the determination of lipase activity.…”

“…18,21,22 Although higher animals and plants also produce them, most lipases currently employed in biotechnological applications have been isolated from microorganisms, mainly fungi and bacteria. 21,23 From the economic and industrial point of view, microorganisms present advantages over higher animals and plants as sources of lipases, due to the high cost of enzyme isolation from higher organisms 24 since microorganisms grow fast and are easily handled. Commercial lipases of fungal origin are generally extracellular enzymes, although there is considerable evidence for the activity of myceliumbound lipases and their study has received attention in recent years.…”

“…23,[25][26][27] The industrial demand for new sources of lipases has continued to stimulate the isolation and screening of new lipolytic microorganisms. 23 The immense biological diversity in the Amazon region and the importance of fungi as enzyme sources, has led to the search for new biocatalysts with special characteristics and possibilities for application in biotechnological processes. 16,28 The access to a wide range of lipase types has made them even more desirable for two additional reasons: (i) from the large number of lipases cited in the literature, only the enzymes of a few species have been shown to be stable and have biosynthetic capacities suitable for routine use in organic reactions; and (ii) many important problems remain unsolved in the application of lipases in certain industrial processes.…”

“…Lipases bound to the cell, both in fungi and in bacteria, also have great stability in organic solvents. 23,[25][26][27] The industrial demand for new sources of lipases has continued to stimulate the isolation and screening of new lipolytic microorganisms. 23 The immense biological diversity in the Amazon region and the importance of fungi as enzyme sources, has led to the search for new biocatalysts with special characteristics and possibilities for application in biotechnological processes.…”