| Substrate crystallinity, particle size, lignin and cellulose content were studied with respect to their individual effects on hydrolysis by the Trichoderma reesei QM 9414G cellulase system with ethanol production by Candida brassicae IFO 1664 in simultaneous saccharification fermentation. Substrates were pretreated in a Cyclotec lab mill, ball attritor (wet), ball attritor (dry), 0.5N NaOH KMnO(,4), and 1.0N H(,2)SO(,4). Maximum conversions to ethanol as % of theoretical were as follows: wet attrition of Avicel PH 105 (92.0), pulp mill primary clarifier sludge (45.7), and newspaper (90.2); dry attrition of corrugated cardboard (73.0), and saw mill waste (52.8); and 0.5N NaOH pretreatment of bagasse (74.5), and rice straw (111.2).;X-ray crystallinity indices following hydrolysis (CI(,48)) decreased in 55.0% of all cases and in 9.5% remained constant while only 35.5% increased as expected. This indicated that crystalline cellulose was not necessarily more resistant to hydrolysis than amorphous cellulose. Increasing absolute change in CI from CI(,0) to CI(,48) was the most reliable indicator of enzymatic hydrolysis. This correlation held true in four of the seven substrate cases.;Average substrate particle size prior to hydrolysis for < 32-947(mu)m showed no correlations with either conversions or CI(,0) values.;Substrate lignin content prior to hydrolysis from 0-18% of dry weight showed a correlation between decreasing lignin content due to either NaOH or KMnO(,4) pretreatment and increasing conversions. Based on conversions of previously unprocessed and processed substrates, the nature of lignin association with cellulose is of greater importance than the quantity of lignin.;X-ray crystallinity indices of substrates prior to hydrolysis (CI(,0)) indicated the relative distribution of crystalline (highly ordered) and amorphous (unordered) cellulose. Decreasing CI(,0) values for newspaper (84.1-53.1), and saw mill waste (75.0-60.0) were reliable indicators of increasing susceptibility to hydrolysis. The CI(,0) values were also reliable indicators for cardboard and wet attrited substrates; however, in these cases increasing CI(,0) values (52.8-86.8 and 52.9-78.9) were indicative of increasing conversions. In all other cases, CI(,0) values were unreliable as indicators of potential hydrolysis. Substrate CI(,0) values should be regarded only as a measure of order and not of either accessibility or susceptibility to hydrolysis.;Substrate cellulose content prior to hydrolysis from 37-97% of dry weight showed no correlations with conversions even though increasing substrate cellulose was associated with increasing CI(,0) values. |
