The ABC transporter ABC40 encodes a phenylacetic acid export system in Penicillium chrysogenum

The filamentous fungus Penicillium chrysogenum is used for the industrial production of beta-lactam antibiotics. The pathway for beta-lactam biosynthesis has been resolved and involves the enzyme phenylacetic acid CoA ligase that is responsible for the CoA activation of the side chain precursor phenylacetic acid (PAA) that is used for the biosynthesis of penicillin G. To identify ABC transporters related to beta-lactam biosynthesis, we analyzed the expression of all 48 ABC transporters present in the genome of P. chrysogenum when grown in the presence and absence of PAA. ABC40 is significantly upregulated when cells are grown or exposed to high levels of PAA. Although deletion of this transporter did not affect beta-lactam biosynthesis, it resulted in a significant increase in sensitivity to PAA and other weak acids. It is concluded that ABC40 is involved in weak acid detoxification in P. chrysogenum including resistance to phenylacetic acid. (C) 2012 Elsevier Inc. All rights reserved.