Sequential acid and enzymic hydrolysis of sugar beet pulp

Abstract

Fermentable sugars from beet pulp were obtained in a two‐stage hydrolytic process. The first stage involved mild acid treatment to hydrolyze the hemicellulose, producing a pentose‐rich syrup and a cellulose‐rich fraction. The second stage was the enzymic saccharification of the cellulose fraction with fungal cellulases to produce a glucose‐rich syrup. The acid hydrolysis stage was evaluated to optimize the type of acid, acid concentration, temperature and reaction time. Solubilization was markedly temperature‐dependent, whereas the specificity of hemicellulose degradation depended on the type of acid utilized. The effects of different reaction times, enzyme‐to‐substrate ratios and particle sizes on the enzymic stage were studied. Both saccharification rate and the extent of final conversion to glucose were markedly affected by the enzyme‐to‐substrate ratio. Sugars recovered from the enzymic degradation of cellulose were partially fermented by Saccharomyces cerevisiae ATCC 4126.

Saccharification and protein enrichment of sugar beet pulp byPleurotus florida

“…The different approaches to this topic range from chemical and enzymatic hydrolysis releasing fermentable sugars (Moloney et al, 1984;Schaffeld et al, 1987;Hassanien et al, 1990), to anaerobic digestions giving biogas (Stoppok and Buchholz, 1984). One more way to convert and upgrade this by-product is to cultivate directly on it microorganisms able to degrade the fibrous material to fermentable sugars.…”