3.4. Phenolic compounds in rice straw hydrolysate
Furthermore, the effect of trace degradation products such as phenolic compounds should not been disregarded. Therefore, GC-MS was employed in this study to qualitatively explore he composition of phenolic compounds in the hydrolysate and the changes after overliming detoxification. Fig.2 was shown the chromatograph from GC-MS analysis for different phenolic compounds in rice straw hydrolysate. Among these compounds that have been identified, Vanillin (4-hydroxy-3-methoxybenzaldhyde) and sringaldehyde are commonly considered as fermentation inhibitors for ethanol production. Previous studies have indicated that phenolic compounds can partition into biological membranes and cause loss of integrity, thereby having inhibitory effect in the fermentation [9]. The most abundant furan-derived compounds in the hydrolysate were almost removed in the detoxified hydrolysate. This result was similar to that the removal of furfural from the overliming process.