As shown in Fig. 3, the ethanol concentration in the bioreactor was found to be 16.870.35 g l1 , when no air/N2 was flushed through bioreactor, whereas, the ethanol concentration in the bioreactor and condensate were found to be 1.570.05 g l1 and 56.370.25 g l1 , respectively, when N2 was flushed through bioreactor for in-situ ethanol recovery