초록
<P><B>Abstract</B></P> <P>To achieve sucrose-metabolizing capability, different sucrose utilization operons have been introduced into <I>E. coli</I> that cannot utilize sucrose. However, these engineered strains still suffer from low growth rates and low sucrose uptake rates. In this study, cell surface display system was adopted in engineered <I>E. coli</I> AFP111 for succinic acid production from sucrose and molasses directly. Invertase (CscA) from <I>E. coli</I> W was successfully anchored to outer membrane by fusion with OmpC anchoring motif, and the displayed CscA showed high extracellular activity. Compared with the sucrose permease system, the cell surface display system consumed less ATP during sucrose metabolism. When less ATP was consumed by AFP111/pTrcC-<I>cscA</I>, the succinic acid productivity from sucrose was 23% higher than that by AFP111/pCR2.1-<I>cscBKA</I> that having the sucrose permease system. As a result, 41gL<SUP>−1</SUP> and 36.3gL<SUP>−1</SUP> succinic acid were produced by AFP111/pTrcC-<I>cscA</I> from sucrose and sugarcane molasses respectively at 34h in 3-L fermentor during dual-phase fermentation. In addition, 79gL<SUP>−1</SUP> succinic acid was accumulated with recovered AFP111/pTrcC-<I>cscA</I> cells at the end of dual-phase fermentation in 3-L fermentor, and the overall yield was 1.19molmol<SUP>−1</SUP> hexose.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CscA was anchored to outer membrane of microbial cells by fusion with OmpC. </LI> <LI> AFP111/pTrcC-<I>cscA</I> showed high extracellular invertase activity. </LI> <LI> Surface display system consumed less ATP than permease system during sucrose uptake. </LI> <LI> 37.3gL<SUP>−1</SUP> succinate was obtained at 36h in AFP111/pTrcC-<I>cscA</I> from molasses. </LI> <LI> The yield of 1.2molmol<SUP>−1</SUP> hexose was generated in AFP111/pTrcC-<I>cscA</I> from molasses. </LI> </UL> </P>