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SummaryPartial acid hydrolysis was studied as a pretreatment to enhance enzymatic hydrolysis. Such a pretreatment Gas carried out in a continuous flow reactor on oak, corn stover, newsprint, and Solka Floc at temperatures ranging from 160 to 220°C, acid concentrations ranging from 0 to 1.2%, and a fixed treatment time of 0.22 min. The resulting slurries and solids were then hydrolyzed with Trichoderma reesei QM 9414 cellulase at 50°C for 48 hr. For all substrates except Solka Floc, increased glucose yields were achieved during enzymatic hydrolysis of the pretreated materials as compared to hydrolysis of the original substrates. In several cases, after pretreatment, 100% of the potential glucose content of the substrate was converted to glucose after 24 hr of enzymatic hydrolysis. It is felt that the increased glucose yields achieved after this pretreatment are due to the acid's removal of hemicellulose, reduced degree of polymerization, and possibly due to a change in the crystal structure of the cellulose.

The effect of the oxygen supply pattern on the onset and development of the lignolytic enzyme system of Phanerochaete chrysosporium was studied in submerged culture employing the serum bottle approach. Periodic or continuous flushing through the head phase, and continuous bubbling through the liquid phase with either oxygen (O2) or air were applied. The nature of the O2 supply had a crucial regulatory effect not only on the formation of lignin-degrading peroxidases but also on their decay and on the production of extracellular protease activity and polysaccharides. Continuous oxygenation or aeration increased the glucose consumption rate, extracellular protease activity and polysaccharides. Gassing with air, whether continuous or periodic, sustained Mn-peroxidase activity while ligninase was undetectable. Continuous 02 supply speeded up ligninase decay, displaying a sharper maximum, while a broader maximum and slower decay of ligninase activity were observed when supplying periodic 02. Cultures initially grown with free exposure to air displayed a higher but sharper ligninase activity maximum when shifted to continuous rather than periodic O2 supply. In general, the higher levels of either polysaccharides or protease activity corresponded to the lower levels and faster decay of ligninase and Mn-peroxidase activities.