The urge for the use of green biotechnological alternatives such as biocatalysis require stable and catalytically active enzymes that can be exposed to a vast range of chemical reactions conditions and used in different industrial applications. Hydrolases are needed for the synthesis of chiral building blocks with high chemo- regio- and stereoselectivity. With the aim of increasing this enzyme platform and finding new hydrolyses with high stability in a broad range of organic solvents, 153 moderate halophilic bacteria from tropical solar salterns at Cabo Rojo (Puerto Rico) were cultivated using Marine Broth and screened for extracellular esterase lipase, protease and epoxide hydrolyses activities. The screening was performed in 96-well plates using a para-nitrophenol colorimetric assay for esterase, lipase and protease and adrenaline test for epoxide hydrolase. 45 isolates exhibited esterase activity, 12 were positive for lipases, 47 for proteases and 28 for epoxide hydrolases. The positive hits were further assayed for stability at increasing concentration of selected organic solvents, acetonitrile, dioxane and DMSO (15%, 30% and 50% (v/v)). Three esterases, one lipase, two proteases and two epoxide hydrolyses showed high activity in organic solvents even after 24 hours incubation at 25 °C. These enzymes and related bacteria were characterized for optimum, pH, temperature and salinity. Results show that they belong to moderate halophilic bacteria, and have thermophilic and basophilic characteristic.<br/>The semipurified enzymes were tested for their enantioselectivity in the kinetic resolution of chiral alcohols, amines and epoxides. Moderate to good enantioselectivity was observed.<br/>These results suggest that hydrolases from moderate halophilic bacteria are promising enzymes and could be used in biocatalytic processes.

Screening and partial characterization of moderate halophilic hydrolases with good stability in organic solvents

253rd National Meeting (2017)

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