Cloning and screening of the putative hexokinase genes from Rhizopus oryzae and their heterologous expression in Saccharomyces cerevisiae

A filamentous fungus, Rhizopus oryzae (R. oryzae) is one of the ideal candidates for ethanol and lactic acid production due to its ability to grow on renewable carbon sources.In this study, the nucleotide sequence of hexokinases and glucokinase from S. cerevisiae was found on the NCBI site ( http://www.ncbi.nlm.nih.gov/blast/Blast.cgi ) were used. With these nucleotide sequences, a blast search was done on the R. oryzae genome database ( http://www.broad.mit.edu/annotation/genome/rhizopus_oryzae/Home.html ) and ten probable genes were obtained. cDNA was synthesized from the total RNA and PCR products of the seven of these putative genes were determined using the primers designed for them.The results of the sequences and the complementation studies revealed that three of these seven putative genes were expressed in R. oryzae and the growth was observed on selective media.