Detection of ionic liquid stable cellulase produced by the marine bacterium Pseudoalteromonas sp. isolated from brown alga Sargassum polycystum C. Agardh

Abstract

An extracellular cellulase produced by marine bacterium Pseudoalteromonas sp. was studied for its activity and stability in six different ionic liquids (ILs) over a wide range of concentrations (1-20% v/v) and compared with aqueous medium as control. Enzyme showed its optimal activity at 45°C and at pH 5 in control. Although the activity varied with the type of IL and its concentration used, the activity measured at 5% (v/v) was maximum with [EMIM]Br followed by [EMIM]Ac, [BMIM]Cl, [C2MIM][CH3SO3], [BMIM][OTF] and [BMPL][OTF] with 115%, 104.7%, 102.2%, 98.33%, 93.84% and 92.67%, respectively, and >80% activity at 15% (v/v) in all ILs. The enzyme stability at 5% (v/v) IL concentration for 36h was superior to commercial cellulase. The cellulase activity enhanced by 1.35- to 1.72-fold over control when 5% (v/v) IL based reaction medium with algal biomass was used and thus showed potentials for saccharification of biomass in a single step process.