A Rhizopus oryzae lipase (ROL) has been expressed in Pichia pastoris as a reporter gene using two different regulated promoters. Both phenotypes, Mut s and Mut+, have been used for the expression under the control of alcohol oxidase 1 promoter (PAOX1). Moreover, the new formaldehyde dehydrogenase 1 promoter (PFLD1) has been tested. PFLD1 allows the design of methanol-free culture strategies, being methylamine a less volatile and flammable inducer. The comparison in batch and fed-batch cultures of the two promoters has shown that Muts (PAOX1) is somewhat more efficient than PFLD1 and Mut+ (PAOX1) systems, with a 1.1- and 1.4-fold higher specific productivity (U lipase/g biomass h), respectively. However, the productivity in all three systems was very similar (2500 U lipase/l h). These results demonstrate that the expression of heterologous proteins under the transcriptional control of PFLD1 is a promising alternative to the well-known PAOX1. © 2005 Elsevier B.V. All rights reserved.
- Fed-batch culture
- Pichia pastoris