Concurrent production of cellulase and xylanase from Trichoderma reesei NCIM 1186: enhancement of production by desirability-based multi-objective method.

Application of multiple response optimizations using desirability function in the production of microbial metabolites improves economy and efficiency. Concurrent production of cellulase and xylanase in Trichoderma reesei NCIM 1186 using an agricultural weed, Prosopis juliflora pods, was studied. The main aim of the study was to optimize significant medium nutrient parameters for maximization of cellulase and xylanase by multi-objective optimization strategy using biomass. Process parameters such as the nutrient concentrations (pods, sucrose, and yeast extract) and pH were investigated to improve cellulase and xylanase activities by one factor at a time approach, single response optimization and multi-objective optimization. At the corresponding optimized process parameters in single response optimization, the maximum cellulase activity observed was 3055.65 U/L where xylanase highest activity was 422.16 U/L. Similarly, the maximum xylanase activity, 444.94 U/L, was observed with the highest cellulase activity of 2804.40 U/L. The multi-objective optimization finds a tradeoff between the two objectives and optimal activity values in between the single-objective optima were achieved, 3033.74 and 439.13 U/L for cellulase and xylanase, respectively.

Immobilization of levan-xylanase nanohybrid on an alginate bead improves xylanase stability at wide pH and temperature.

Despite the sustainable availability, levan, a fructose based natural polysaccharide has not received significant attention in the development of enzyme immobilization technology. Herein, we prepared levan-xylanase (LXy) nanohybrid and characterized by scanning electron microscopy, particle size analyzer and zeta potential. To prevent the enzyme leakage from the nanohybrid, LXy was immobilized onto an alginate beads (NaAlg). Immobilization yield was optimized using a statistical method, central composite design. A maximum immobilization yield of 95.3% was achieved at 2.13% (w/v) of sodium alginate, 2.14% (w/v) of calcium chloride, 64min of curation time and 1.4mm bead size. Immobilized LXy retains nearly 80% of the enzyme activity at a wide range of temperature (20-90°C) and pH (3-10). Immobilization of LXy onto NaAlg increases the activation energy from 28.50Jmol-1K-1 to 39.38Jmol-1K-1. Collectively, this result implies that LXy immobilized onto NaAlg increases the enzyme stability and retains its activity.