ABSTRACT
A continuous stirred reactor fed maltose as substrate was used to show that acid hydrolyzed starch-g-polyacry-lonitrile and other polysaccharide graft copolymers can bind and retain significant quantities of active glucoamy-lase. Glucose productivities up to 2.7 g/g carrier/h were observed with the immobilized glucoamylase, and half-lives up to 1800 h were indicative of activity longevity. Factors influencing the immobilized enzyme activity and first-order decay rate included temperature, p(H), and carrier composition. In all cases, maltose was converted quantitatively to glucose with no evidence of reversion product formation.
ABSTRACT
Treatment of wheat straw with 1N trifluoroacetic acid (TFA) for 7 h at reflux temperature yielded 23% xylose based upon initial straw weight. This corresponds to about an 80% xylose yield based on the xylan content of the hemicellulose. The cellulose component of wheat straw was largely unaffected, as evidenced by low glucose yields. Decomposition of xylose by prolonged refluxing (23 h) was minimal in 1N TFA compared to 1N HCl. Treatment of wheat straw with refluxing 1N TFA converts about 10% of the lignin initially present in straw into water-soluble lignin fragments. Fermentation of the xylose-rich wheat straw hydrolyzate to ethanol with Pachysolen tannophilus was comparable to the fermentation of reagent grade xylose, indicating that furfural and toxic lignin by-products were not produced by 1N TFA in sufficient amounts to impair cell growth and ethanol production. Cellulase treatment of the wheat straw residue after TFA hydrolysis resulted in a 70-75% conversion of the cellulose into glucose.
ABSTRACT
Two-phase mixtures of gasoline, water, and ethanol were dehydrated with both starch and saponified starch-g-polyacrylonitrile (HSPAN). Whereas starch absorbed ethanol as well as water, HSPAN selectively absorbed the water component, allowing ethanol to dissolve in the gasoline phase.
