초록
<P><B>Abstract</B></P> <P>Bio-oil derived from Pyrolysis of lignocellulosic biomass contains appreciable amounts acetic acid, which can be used as substrate for growing microalgae <I>Chlamydomonas reinhardtii</I>. However, the toxic compounds in the bio-oil inhibit the cell growth. This work is to develop alkaline treatment methods to reduce the toxicity and improve fermentability of acetic acid rich bio-oil. When growing in raw bio-oil without any detoxification treatment, the algae can only tolerate up to 0.1 wt% of bio-oil. Treatment with KOH, NaOH and Ca(OH)<SUB>2</SUB> significantly reduced the toxicity and consequently improved the fermentability of bio-oil. The bio-oil tolerant level by microalgae depended on the alkali species used. Among the three alkali species, Ca(OH)<SUB>2</SUB> proved the most effective detoxification reagent. Inhibitory compounds such as furans, phenols, ketones, aldehydes, ethers, esters, alcohols were removed by Ca(OH)<SUB>2</SUB> treatment through precipitation. The detoxification mechanisms by the Ca(OH)<SUB>2</SUB> -based treatment were also explored. The synergistic effect of alkaline pH, high temperature, and presence of Ca<SUP>2+</SUP> played an important role for the precipitation of those compounds, and the consequent detoxification. Collectively, the results shows alkali, particularly Ca(OH)<SUB>2</SUB>-based, treatment is an effective for reducing the toxicity of the pyrolysis derived bio-oil as fermentative substrate for microalgae growth. The microalgae can tolerant Ca(OH) <SUB>2</SUB>-treated bio-oil up to 5.5 wt%, which was 55 times higher than algal tolerance level of untreated bio-oil.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fast pyrolysis of lignocellulosic biomass produces acetic acid rich bio-oil as a potential substrate for algal growth. </LI> <LI> Crude acetic acid-rich bio-oil is toxic to algal growth due to a variety of compounds contained. </LI> <LI> Alkaline treatment is an effective way for reducing bio-oil toxicity and enhancing it fermentability. </LI> <LI> Ca(OH)<SUB>2</SUB> treatment resulted in the best detoxification due to the synergistic effect of pH, temperature, and calcium ion. </LI> </UL> </P>