• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.672-679
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• 2022

Microbial lipases are used widely in the synthesis of various compounds due to their substrate specificity and position specificity. 4-Ethyl malate (4-EM) made from diethyl malate (DEM) is an important starting material used to make argon fluoride (ArF) photoresist. We tested several microbial lipases and found that Photobacterium lipolyticum M37 lipase position-specifically hydrolyzed DEM to produce 4-EM. We purified the reaction product through silica gel chromatography and confirmed that it was 4-EM through nuclear magnetic resonance analysis. To mass-produce 4-EM, DEM hydrolysis reaction was performed using an enzyme reactor system that could automatically control the temperature and pH. Effects of temperature and pH on the reaction process were investigated. As a result, 50℃ and pH 4.0 were confirmed as optimal reaction conditions, meaning that M37 was specifically an acid lipase. When the substrate concentration was increased to 6% corresponding to 0.32 M, the reaction yield reached almost 100%. When the substrate concentration was further increased to 12%, the reaction yield was 81%. This enzyme reactor system and position-specific M37 lipase can be used to mass-produce 4-EM, which is required to synthesize ArF photoresist.

• Food Science and Preservation
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• v.11 no.3
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• pp.417-423
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• 2004

Botanical antimicrobial agent-grapefruit seed extract mixture (BAAG) have an unknown compounds which exhibit the antibiotic activities aganist microorganisms including bacteria and fungi. We have examined the effects of BAAG on the physiological function of Botrytis cinerea which was isolated from necrotic lesions of decayed fruits and vegetables such as cucumbers, grapes, tomatoes, and red peppers during storage. In the results of enzymatic activities related to the energetic metabolism there was no inhibitory effect of BAAG on the activities of several enzymes in vitro including glucose 6-phosphate dehydrogenase and malate dehydrogenase, while there was inhibitory effect of BAAG on the activities of hexokinase and succinate dehydrogenase. O-nitrophenyl-$\beta$-D-galactopyranoside(ONPG), the artificial substrate of $\beta$-galactosidase was hydrolyzed in the presence of BAAG, indicating that the membrane was pertubated by the BAAG. From the results we suggested that the antibiotic activity of BAAG is due to the change of membrane permeability of the cell. BAAG was fractionated and purified by silica gel and sephadex column chromatography. Among active fractions two peaks were identified as naringin and limonin when they were analyzed by by NMR and Fast atomic bombardment.