Arthrographis curvata and Rhodosporidium babjevae as New Potential Fungal Lipase Producers for Biotechnological Applications

Abstract Fungi have always attracted a lot of attention as they are able to produce a vast repertoire of enzymes that find a broad spectrum of uses in biotechnological and industrial fields. Undoubtedly, one of the most promising biocatalysts is the lipase, which has been widely used for the biotransformation of a number of commercial products due to its high stability, high catalytic efficiency, versatility and selectivity, making it one of the most attractive and best-studied enzymes. In this study we report the isolation and molecular identification of new lipase-producing fungi from different environmental samples from Morocco. The production and activity of extracellular lipases, at different parameters, was evaluated using the Rhodamine B agar, submerged fermentation and biochemical methods. Two fungal strains Arthrographis curvata and Rhodosporidium babjevae, were isolated and found to produce large amounts of lipases. The optimal activity of the extracellular lipase was detected at 40°C and pH 9.0 for A. curvata and at 40 °C and pH 8.0 for R. babjevae. This study add new information at the growing list of fungal species producing lipases with improved physicochemical proprieties which could constitute a new line of research for further studies and to be exploited for industrial or bioremediation purposes.

Taxonomic study and partial characterization of antimicrobial compounds from a moderately halophilic strain of the genus Actinoalloteichus

A moderately halophilic actinomycete strain designated AH97 was isolated from a saline Saharan soil, and selected for its antimicrobial activities against bacteria and fungi. The AH97 strain was identified by morphological, chemotaxonomic and phylogenetic analyses to the genus Actinoalloteichus. Analysis of the 16S rDNA sequence of strain AH97 showed a similarity level ranging between 95.8 percent and 98.4 percent within Actinoalloteichus species, with A. hymeniacidonis the most closely related. The comparison of the physiological characteristics of AH97 with those of known species of Actinoalloteichus showed significant differences. Strain AH97 showed an antibacterial and antifungal activity against broad spectrum of microorganisms known to be human and plant pathogens. The bioactive compounds were extracted from the filtrate culture with n-butanol and purified using thin layer chromatography and high pressure liquid chromatography procedures. Two active products were isolated, one hydrophilic fraction (F1) and another hydrophobic (F2). Ultraviolet-visible, infrared, mass and ÕH and 13C nuclear magnetic resonance spectroscopy studies suggested that these molecules were the dioctyl phthalate (F2) and an aminoglycosidic compound (F1).