Tranglycosylation reactions using glycosyl hydrolases from Thermotoga neapolitana, a marine hydrogen-producing bacterium

The use of the extremophilic marine bacterium Thermotoga neapolitana (DSM 4359) for the bioproduction of hydrogen using complex carbohydrates as feedstock has been recently described in a patent. In this growth condition glycosyl hydrolases can be well expressed. An important issue to plan economical feasibility of biological hydrogen production comprises techniques for recovering useful materials such as physiologically active biomolecules from biomasses grown in large quantities. The present paper describes a series of enzymatic transglycosylation reactions performed using the crude homogenate of T. neapolitana. The study is focused on synthetic features of the transglycosylating enzymes. Xylosidase/xylanase activity seems to be the most abundant leading to convenient syntheses of interesting series of pure ([3-1,4)-xylooligosaccharides of different aglycones such as 1-hexanol (producing promising candidates for new surfactants), 9-fluorene methanol (obtaining anti-HSV agents), 1,4-butanediol (for the synthesis of new glycolipids), and geraniol (producing aroma compounds). Furthermore, the regioselectivity during galactose, fucose, glucose, and mannose enzymatic transfers is also investigated. The knowledge of synthetic characteristics of all these enzymes will be useful in the feasibility evaluation of large-scale processes of the biohydrogen production based on T. neapolitana.