Highly efficient immobilization of endo-1,3-β-d-glucanases (laminarinases) from marine mollusks in novel hybrid polysaccharide-silica nanocomposites with regulated composition

A novel immobilizing method developed previously by ourselves was successfully used to entrap endo-1,3-β-d-glucanases (laminarinases) separated from marine bivalvia Spisula sacchalinensis (glucanase LIV) and Chlamys albidus (glucanase Lo) into hybrid polysaccharide-silica nanocomposite materials by means of the sol–gel processing. Its main advantage over the current immobilizing procedures is that the entrapment conditions are dictated by the enzymes, but not the processing. It was shown that both the 1,3-β-d-glucanases retained or even had sometimes an increased activity after the immobilization. At the same time, their characteristics (optimal pH, temperature and ionic strength) noticeably were not changed. They provided a depth of hydrolysis of laminaran comparable with that caused by free enzymes in solutions. Furthermore, glucanase Lo retained its glucanosyl transferase activity, affording an enzymatic synthesis of biologically active 1,3;1,6-β-d-glucan, called translam, from the initially inactive laminaran. It was also demonstrated that the laminarinase entrapment into the hybrid nanocomposites led to a prominent increase of thermal and long-term stability that was particular striking in a case of such a labile enzyme as the glucanase Lo. By varying the nanomaterial composition, its influence on the glucanase activity was found that differed for the studied enzymes.