engleski

Streptomycetes are a source of hydrolytic enzymes with potential in lipid biotransformation

The sequencing of the genomes of several streptomycete species revealed that these bacteria have great potential for synthesis of an interesting subclass of lipolytic enzymes. These GDS(L) hydrolyses have multifunctional properties with potential for use in the hydrolysis and synthesis of important ester compounds of biotechnological interests. In the last decade, our group has done intensive research on this class of enzymes isolated from Streptomyces. Several genes encoding GDS(L) lipases have been cloned so far from S. rimosus and S. coelicolor. The enzymes were expressed, purified from heterologous and homologous host and extensively biochemically characterized. These enzymes might have significant biotechnological potential due to high working temperature ; stability in organic solvents, activity over a broad range of pH and temperature, and the ability to hydrolyze numerous classes of substrates. The most pronounced difference between S. rimosus lipase (SrL) and S. coelicolor lipase (ScL) is in acyl chain length specificity, as SrL shows maximal activity toward substrates with chain lengths C8-C10, and ScL shows preference for substrates with longer acyl-chain lengths (C14). Further, enzymes are stable in several tested organic solvents, while some solvents even increase their activity (eg. dioxane). Although the structures of enzymes have not been solved, both enzymes are predominantly α-helical proteins, as shown by CD spectroscopy. Site- directed mutagenesis has enabled us to identify catalytically important amino acid residues.

SGNH lipolytic enzymes ; Streptomyces ; potential for application

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