Formulation of an optimized synergistic enzyme cocktail, HoloMix, for effective degradation of various pre-treated hardwoods

- Synergism between CelMix and XynMix improved hardwood biomass hydrolysis.
- XynMix requirement was highly biomass composition/pre-treatment dependent.
- HoloMix reached 70-100% sugar yields after 24 h.
- Biomass pre-treatment with a laccase, AbLac, improved its hydrolysis by HoloMix.
- An efficient optimized hardwood biomass degrading cocktail was formulated.

In this study, two selected hardwoods were subjected to sodium chlorite delignification and steam explosion, and the impact of pre-treatments on synergistic enzymatic saccharification evaluated. A cellulolytic core-set, CelMix, and a xylanolytic core-set, XynMix, optimised for glucose and xylose release, respectively, were used to formulate HoloMix cocktail for optimal saccharification of various pre-treated hardwoods. For delignified biomass, the optimized HoloMix consisted of 75%:25% protein dosage, CelMix: XynMix, while for untreated and steam exploded biomass the HoloMix consisted of 93.75%:6.25% protein dosage. Saccharification by HoloMix (27.5 mg protein/g biomass) for 24 h achieved 70-100% sugar yields. Pre-treatment of the hardwoods (especially those with a higher proportion of lignin) with a laccase, improved saccharification by HoloMix. This study provided insights into enzymatic hydrolysis of various pre-treated hardwood substrates and showed the same lignocellulolytic cocktail comparable to/if not better than commercial enzyme preparations can be used to efficiently hydrolyse different hardwood species.