A study on critical associations of media components on enhanced cellulase production from wild Trichoderma viride and cellulase immobilization on iron-oxide magnetic nanoparticles

Abstract

Aim: The current study is a preliminary step towards enhancing the cellulase productivity in wild Trichoderma viride which will enable robust valorization of non-edible lignocellulosic biomass through co-generative enzymatic saccharification, specifically concentrating on influence of individual media components on biomass growth and cellulase productivity. Further, cellulase immobilization on iron-oxide magnetic nanoparticles was also achieved that can increase the shelf life of the enzyme. Methodology: The cellulase production in the wild Trichoderma viride was enhanced using media design and formulation. EDC {1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide} functionalized iron-oxide nanoparticles were chosen to act as carriers for cellulase immobilization. The binding efficiency and relative activity were measured in addition to optimal pH and temperature for cellulase bound iron-oxide nanoparticles. Further, the hydrolysis efficiency of immobilized cellulases was also measured after which it was subjected to consecutive hydrolytic cycles to calculate the recycle rate. Results: A maximum growth rate of 60 PCV (Packed cell volume) and total cellulase activity of 7.4 U ml-1 was obtained on media design and formulation. 82.5% binding efficiency was achieved on EDC functionalized iron-oxide magnetic nanoparticles which showed good stability at 5pH and 500C. There was 44.4% activity loss after 5 consecutive hydrolytic cycles which showed steady decline with increased cycle number and finally at the end of the 10th hydrolytic cycle, 22.2% of total relative activity was retained. Interpretation: Unprecedented total cellulase activity from a wild strain was obtained through media design. The stability of cellulases was further enhanced using iron-oxide magnetic nanoparticle immobilization. Key words: Cellulases, Immobilization, Iron-oxide magnetic nanoparticles, Submerged fermentation, Trichoderma viride