Abstract

Microorganisms are considered one of the most promising niches for the prospecting, producing, and applying bioactive compounds of biotechnological interest. Among them, bacteria offer certain distinctive advantages due to their short life cycle, low sensitivity to seasonal and climatic changes, easy scaling, and ability to produce unknown bioactive metabolites with biotechnological interest. Developing new biological products, such as enzymes, dyes, antibiotics, and others with high potential use for biotechnological applications, continues to stimulate the search for microorganisms in extreme environments. In recent years, the study of Antarctic ecosystems and their microorganisms has received more attention because psychrophilic microorganisms—mainly bacteria and their enzymes—have assumed considerable importance for biotechnological applications. At our Laboratory, we have characterized 300 Antarctic bacteria. The screening for biologically active products showed that all the evaluated strains produced at least one extracellular enzyme at 4 °C, protease, gelatinase, and cellulase, the most common. Another screening revealed 81 out of 304 strains with β-galactosidase activity. The strain Se8.10.12 showed the highest enzymatic activity. Morphological, biochemical, and molecular characterization based on whole-genome sequencing confirmed it as the first Rahnella inusitata isolate from the Antarctic, which retained 41–62% of its β-galactosidase activity in the cold (4 °C–15 °C). Three β-galactosidases genes were found in the R. inusitata genome, which belongs to the glycoside hydrolase families GH2 (LacZ and EbgA) and GH42 (BglY). We highlighted that further efforts for the commercial production of a new diversity of cold-active enzymes might promote its regular use in other areas, such as dairy whey, to produce additional valuable bioproducts.