Inhibition efficiency evaluation of lignocellulose-derived compounds for bioethanol production

The toxicity and inhibition efficiency of lignocellulose-derived compounds on two kinds of bacteria were evaluated based on Quantitative Structure-Activity Relationship method, which could guide us to eliminate fermentation inhibitors existed in hydrolysates specifically. The results revealed that phenols exhibited the most significant toxicity on microbes, in which the functional group attached to benzene ring could dramatically influence toxicity degree. Furans showed moderate toxicity on microbes, however, short chain fatty acids exhibited feeble toxicity. GC-MS analysis identified inhibitors in rice straw hydrolysates after alkali-pretreatment as main constituent of phenols and acids, the concentration of which were 1.965 mM and 2.965 mM, respectively. Moreover, inhibition efficiency of these inhibitors was evaluated based on their toxicity and concentration. The results showed that inhibition efficiency of long chain fatty acids and phenol acids were significantly more enormous than that of other compounds, in which octadecanoic acid and ferulic acid had maximum inhibition efficiency value.