[Comparison of different transformation methods for Monascus sp].

In order to facilitate the producer of polyketide pathway, four different transformation methods were tested and compared in an attempt to develop the genetic transformation system of Monascus sp. Using vector pBC-Hygro, the fungus was transformed to be hygromycin B-resistant, by conventional transformation as well as electroporation based on protoplast, electroporation based on germinated conidia, and restriction enzyme-mediated integration (REMI). Electroporation based on germinated conidia was found to be inappropriate for transforming Monascus sp. due to a low transformation frequency. The conventional transformation and electroporation technique based on protoplasts were thought not to be fit for transforming Monascus sp., due to a low stability of transformants though they yielded up to 135 transformants and 125 transformants per microgrammol/Lol/Le DNA, respectively. Transformant number was increased by 20-fold by REMI (2,500 transformants per microgrammol/Lol/Le DNA) and 70%-75% of them were stable. REMI technique would be very beneficial to the establishment of the genetic transformation system of Monascus sp.