It was reported that glucose recovery of enzymatic hydrolysis
was enhanced if oil palm fronds were SCW pretreated (Goh et al.,
2010). But according to the results of this study, SCW pretreatment
was unsuccessful for biomass of Y. lipolytica. SCW pretreatment is considered to be a hydrolysis without using acid as catalyst. Further
acid hydrolysis of the pretreated biomass reduced glucose
concentration and raised inhibitors concentration. The cell wall
of yeast may not be as rigid as that of lignocellulosic biomass of
plant origin, which contains lignin. Thus yeast cell wall does not require
subcritical water pretreatment. If yeast cell is pretreated, it
results in too high degree of hydrolysis and significant sugar
degradation.