EXHIBIT 23.1
CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We consent to the incorporation by reference in the Registration Statement (Form S-8), pertaining to the 2000 Employee Stock Purchase Plan of Kosan Biosciences Incorporated (“Kosan”), of our reports dated March 14, 2007, with respect to the financial statements of Kosan, Kosan management’s assessment of the effectiveness of internal control over financial reporting, and the effectiveness of internal control over financial reporting of Kosan included in its Annual Report (Form 10-K) for the year ended December 31, 2006 filed with the Securities and Exchange Commission.
/s/ Ernst & Young LLP |
San Francisco, California |
March 14, 2007 |