초록
<P>A novel hybrid fermentation process for the production of biological butanol and lipids was established in this study. The ABE containing broth obtained from the two-stage fermentation was used as the substrate for the batch bio-lipids fermentation. A gas stripping unit was integrated with the bio-lipids bioreactor to separate the ABE products. The carrier gas also provided the sterilized air for the metabolism of oleaginous microorganisms. The effect of inoculation rate on the bio-lipids fermentation was evaluated and optimized. Under the optimized conditions using a synthetic medium (10% of inoculation rate with additional carbon source supplementation), about 87.9% of the initial COD in the ABE fermentation broth was degraded, while ∼6.4 g L<SUP>−1</SUP> of the bio-lipids and ∼82.1 g L<SUP>−1</SUP> of the ABE solvent cumulated in the bio-lipids bioreactor and the condensate of the gas stripping unit, respectively. Moreover, the organic acid by-products in the ABE broth could be reused as the carbon source for microbial lipid production using <I>Rhodotorula sp.</I>, which was not reported before. The hybrid process was further performed using enzymatic hydrolysate of sweet sorghum bagasse as the substrate. When using the hydrolysate directly without detoxification, ∼62.2 g L<SUP>−1</SUP> of the ABE solvents and ∼2.7 g L<SUP>−1</SUP> of the bio-lipids were produced simultaneously with a COD degradation rate of ∼70.1% from the ABE broth. Correspondingly, 0.06 g of the bio-lipids was co-generated with 0.25 g of the ABE products from a mixture of 1 g reducing sugar in lignocellulosic hydrolysate. The hybrid biorefinery process provides an energy saving way for the manufacture of bio-fuels with environmental benefits.</P><BR><BR><P>Graphic Abstract</P><P>An energy saving and environmentally friendly hybrid fermentation process for the production of bio-fuels was investigated in this research.<BR><IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5gc02285a'><BR></P>