Steering the formation of cellobiose and oligosaccharides during enzymatic hydrolysis of asparagus fibre

The enzymatic conversion of cellulosic-rich waste streams of white asparagus into cellobiose and cello-oligosaccharides (COS) is proposed for producing a natural carrier agent. The enzyme cocktail 'Celluclast' was used to steer towards maximum conversion and minimum formation of monosaccharides to obtain an enzymatic hydrolysate with a high glass transition temperature (T-g). Different enzyme loadings and hydrolysis times were tested in combination with a sodium hydroxide pre-treatment of the asparagus fibre. A loading of 700 nkat/g substrate and 7 h of hydrolysis time resulted in the best yield/purity combination, namely a conversion of 36 g/100 g cellulose with 81% celllobiose/COS. The same hydrolysis conditions were tested in a larger bench-scale experiment (conversion of 45 g/100 g cellulose) and the soluble hydrolysates were concentrated and spray-dried. The high T-g (108 degrees C) of the spray-dried hydrolysates of asparagus fibre proves its potential usage as a carrier agent for spray drying.

Automated summary

This study proposed the enzymatic conversion of cellulosic-rich waste streams of white asparagus into cellobiose and cello-oligosaccharides (COS) for producing a natural carrier agent. By optimizing the enzyme loadings, hydrolysis times, and pre-treatment conditions, a high yield/purity enzymatic hydrolysate with a high glass transition temperature (T-g) was obtained. The spray-dried hydrolysates of asparagus fiber showed potential usage as a carrier agent due to their high T-g.