Neutral Avicelase from <em>Serratia marcescens</em> with Denim Biofinishing Potential

Abstract

Screening of 13 avicelase positive bacterial isolates obtained from soil and leaf litter proved isolate L4 to be a potent avicelase producer with highest zone of clearance (25 mm) and Enzymatic index of 1.8. The phylogenetic tree constructed on the basis of 16S rRNA gene sequences revealed its closeness to <em>Serratia marcescens </em> WW4 and was designated as <em>Serratia marcescens</em> L4. Maximum avicelase (8.2 IU) production by <em>S. marcescens</em> was supported at pH 7.0, 30°C with CMC (5 g/L). Avicelase production was repressed by sugars and showed non-dependence on metal ions. Among agrowastes, potato peel supported the highest activity (6.4 IU). The enzyme showed pH and temperature optima of 7.0 and 55°C and retained almost 72% activity at 55°C up to 2 h. Enzymatic biofinishing at pH 7.0, 55°C and 2 h incubation revealed some amount of weight loss, indigo dye and reducing sugar release from the denim fabric. Thus the neutral avicelase of <em>S. marcescens</em> may find application in denim biofinishing with reduced backstaining.