Summary: | Microbial communities inhabiting the Antarctic Ocean show extremophilic adaptations conferring interesting properties to their enzymes, which could be exploited for biotechnology and bioremediation. As use of cold- and salt-tolerant enzymes allows to limit costs, reduce contaminations, and minimize pretreatments[1], we recently screened our Antarctic strain collection, comprising 186 morphologically diverse microorganisms isolated from marine biofilms and seawater from Terra Nova Bay (Ross Sea, Antarctica). The screening highlighted proteolytic (52.2%), lipolytic (38.2%), amylolytic (28%), chitinolytic (8.6%) and laccase-like (13.4%) activities amongst the strains. In particular, a new protein (Ant laccase) belonging to the copper resistance system multicopper oxidase family was characterized, produced by seawater Halomonas sp. strain M68. Ant laccase oxidizes ABTS and 2,6-dimethoxy phenol, and shows good thermostability, maintaining more than 40% of its maximal activity at 10°C. Furthermore, it is salt- and organic solvent-tolerant, paving the way for its use in harsh conditions[2]. Meanwhile, a chitin deacetylaselike activity was identified in Acinetobacter sp. strain c33, isolated from marine biofilm. It proved able to quickly deacetylate para-nitroacetanilide as well as chitosan and colloidal chitin in under 24 hours at 37°C, and was not inhibited by salts. As chitin is currently considered a waste product of the seafood industry, this enzyme could be applied to valorise it by producing higher-value chitosan and chitooligosaccharides under mild conditions[3]. Our efforts show that bioprospecting Antarctic marine microbial biodiversity can lead to the identification of innovative enzymes with promising industrial applications.
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