초록
<P><B>Abstract</B></P> <P>Cheese whey exploitation in a biorefinery manner is proposed involving anaerobic acidogenesis by a UASB mixed anaerobic culture and alcoholic fermentation by kefir. Both cultures were immobilized on γ-alumina. The produced organic acids (OAs) and ethanol could be esterified to obtain a novel ester-based biofuel similar to biodiesel. During acidogenesis, lactic acid-type fermentation occurred leading to 12gL<SUP>−1</SUP> total OAs and 0.2gL<SUP>−1</SUP> ethanol. The fermented substrate was subsequently supplied to a second bioreactor with immobilized kefir, which increased the OAs content (15gL<SUP>−1</SUP>), especially lactic acid, and slightly the ethanol concentration (0.3–0.4gL<SUP>−1</SUP>). To further increase ethanol concentration, a second experiment was conducted supplying whey firstly to the immobilized kefir bioreactor and then pumping the effluent into the acidogenesis bioreactor, resulting in 40% increase of OAs and 10-fold higher ethanol content. The residual sugar was ∼50% of the initial whey lactose; consequently, future research could result to further increase of ethanol and OAs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Successive continuous alcoholic fermentation and acidogenesis of whey. </LI> <LI> UASB culture (acidogenesis) and kefir (alcoholic fermentation) fixed on γ-alumina. </LI> <LI> Alcoholic fermentation-acidogenesis process led to 10-fold higher ethanol content. </LI> <LI> Organic acids production was increased by 2.5-fold. </LI> <LI> The process is promising for new generation ester-based biofuels from whey. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>