A generic model for glucose production from various cellulose sources by a commercial cellulase complex

Abstract

The kinetics of cellulose hydrolysis by commercially available Cellubrix were described mathematically, with Avicel and wheat straw as substrates. It was demonstrated that hydrolysis could be described by three reactions: direct glucose formation and indirect glucose formation via cellobiose. Hydrolysis did not involve any soluble oligomers apart from low amounts of cellobiose. Phenomena included in the mathematical model were substrate limitation, adsorption of enzyme onto substrate, glucose inhibition, temperature dependency of reaction rates, and thermal enzyme inactivation. In addition, substrate heterogeneity was described by a recalcitrance constant. Model parameters refer to both enzyme characteristics and substrate-specific characteristics.Quantitative model development was carried out on the basis of Avicel hydrolysis. In order to describe wheat straw hydrolysis, wheat straw specific parameter values were measured. Updating the pertinent parameters for wheat straw yielded a satisfactory description of wheat straw hydrolysis, thus underlining the generic potential of the model.

Enzyme inactivation by ethanol and development of a kinetic model for thermophilic simultaneous saccharification and fermentation at 50 °C with Thermoanaerobacterium saccharolyticum ALK2

“…The rate constant for thermal inactivation is comparable to that reported for T. reesei cellulase enzymes (Drissen et al, 2007). While second-order deactivation has also been reported for T. reesei component enzymes due to aggregation (Dominguez et al, 1992) and loss of synergy (Gusakov et al, 1982), the exponential decrease in residual activity measured here gave R 2 values greater than 0.9, demonstrating that a first-order approximation was sufficient for modeling total enzyme activity in this system.…”

A mechanistic model of the enzymatic hydrolysis of cellulose

“…6). The halflife of EG2 was set to 4.3 h and the half-life of CBH1 was set to 10.6 h. These are much shorter thermal half-life values than the value of the half-life for a commercial T. reesei cellulase mixture reported in the literature, 42.5 h (Drissen et al, 2007).…”

Effect of nutrient supplementation on ethanol production in different strategies of saccharification and fermentation from acid pretreated rice straw

“…According to Drissen et al [26], the enzymatic preparation Cellubrix is formed from Celluclast by cellobiase (b-glucosidase) addition. The authors reported a b-glucosidase activity of 204 IU mL À1 of Cellubrix by using cellobiose as substrate for activity determination.…”