초록
<P><B>Background</B></P><P>Efficient conversion of plant biomass to commodity chemicals is an important challenge that needs to be solved to enable a sustainable bioeconomy. Deconstruction of biomass to sugars and lignin yields a wide variety of low molecular weight carbon substrates that need to be funneled to product. <I>Pseudomonas putida</I> KT2440 has emerged as a potential platform for bioconversion of lignin and the other components of plant biomass. However, <I>P. putida</I> is unable to natively utilize several of the common sugars in hydrolysate streams, including galactose.</P><P><B>Results</B></P><P>In this work, we integrated a De Ley–Doudoroff catabolic pathway for galactose catabolism into the chromosome of <I>P. putida</I> KT2440, using genes from several different organisms. We found that the galactonate catabolic pathway alone (DgoKAD) supported slow growth of <I>P. putida</I> on galactose. Further integration of genes to convert galactose to galactonate and to optimize the transporter expression level resulted in a growth rate of 0.371 h<SUP>−1</SUP>. Additionally, the best-performing strain was demonstrated to co-utilize galactose with glucose.</P><P><B>Conclusions</B></P><P>We have engineered <I>P. putida</I> to catabolize galactose, which will allow future engineered strains to convert more plant biomass carbon to products of interest. Further, by demonstrating co-utilization of glucose and galactose, continuous bioconversion processes for mixed sugar streams are now possible.</P>