Ag derived from the microbial riboflavin synthesis pathway ..
The bacterial riboflavin biosynthesis pathway
Previously published research on the formation of riboflavin in different riboflavin overproducing organisms indicates that the enzymatic activity of GTP-cyclohydrolase II (RIB1, Figure ) plays a key regulatory role in the riboflavin biosynthetic pathway. Consequently, the overexpression of this gene was the first step for deregulation of riboflavin biosynthesis in P. pastoris. Since initially, the genome sequence of this yeast was not available to us we decided to express the GTP-cyclohydrolase II gene of S. cerevisiae (ScRIB1) .
synthesis pathway for riboflavin ..
High cell density cultures of Pichia pastoris grown on methanol tend to develop yellow colored supernatants, attributed to the release of free flavins. The potential of P. pastoris for flavin overproduction is therefore given, but not pronounced when the yeast is grown on glucose. The aim of this study is to characterize the relative regulatory impact of each riboflavin synthesis gene. Deeper insight into pathway control and the potential of deregulation is established by overexpression of the single genes as well as a combined deregulation of up to all six riboflavin synthesis genes.