title: Enzymatic hydrolysis of lime-pretreated corn stover and investigation of the HCH-1 Model: inhibition pattern, degree of inhibition, validity of simplified HCH-1 Model.
abstract: The inhibition pattern was identified for a reaction system composed of Trichoderma reesei cellulase enzyme complex and lime-pretreated corn stover. Also, the glucose inhibition effect was quantified for the aforementioned reaction system over a range of enzyme loadings and substrate concentrations. Lastly, the range of substrate concentrations and enzyme loadings were identified in which the linear form of the simplified HCH-1 Model is valid. The HCH-1 Model is a modified Michaelis-Menton Model with non-competitive inhibition and the fraction of insoluble substrate available to bind with enzyme. With a high enzyme loading, the HCH-1 Model can be integrated and simplified in such a way that sugar conversion is linearly proportional to the logarithm of enzyme loading. A wide range of enzyme loadings (0.25-50 FPU/g dry biomass) and substrate concentrations (10-100g/L) were investigated. All experiments were conducted with an excess cellobiase loading to ensure the experimental results were not influenced by cellobiose inhibition. A non-competitive inhibition pattern was identified for the corn stover-cellulase reaction system, thereby validating the assumptions of the HCH-1 Model. At a substrate concentration of 10 g/L, glucose inhibition parameters of 0.986 and 0.979 were measured for enzyme loadings of 2 FPU/g dry biomass and 50 FPU/g dry biomass, respectively. At 5 FPU/g dry biomass, glucose inhibition parameters of 0.985 and 0.853 were measured for substrate concentrations of 10 and 100g/L, respectively. The linear form of the HCH-1 Model predicted biomass digestibility for lime-pretreated corn stover over an enzyme loading range of 0.25-50 FPU/g dry biomass and substrate concentration range of 10-100g/L.
authors.affiliation: Albemarle Corporation, Process Development Center, Gulf States Road, Baton Rouge, LA 70805, USA.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: O'Dwyer
authors.forename: Li
authors.initials: L
authors.lastname: Zhu
authors.forename: Cesar B
authors.initials: CB
authors.lastname: Granda
authors.forename: Mark T
authors.initials: MT
authors.lastname: Holtzapple
mesh_terms: D018533:Biomass; D017610:Calcium Compounds / Q000737:chemistry*; D002475:Cellobiose / Q000737:chemistry; D002480:Cellulase / Q000737:chemistry* / Q000302:isolation & purification; D000431:Ethanol / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry* / Q000302:isolation & purification; D006868:Hydrolysis; D007700:Kinetics; D008956:Models, Chemical; D010087:Oxides / Q000737:chemistry*; D014242:Trichoderma / Q000201:enzymology*; D003313:Zea mays / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D005656:Fungal Proteins; D010087:Oxides; D002475:Cellobiose; D000431:Ethanol; C016538:lime; D002480:Cellulase