Membrane bioreactor for increased production of isoprene gas

Abstract

The invention provides improved methods for the production of isoprene from biological materials.

1 - 124 . (canceled) 
     
     
         125 . A method of producing isoprene, the method comprising:
 (a) culturing cells comprising a heterologous nucleic acid encoding an isoprene synthase polypeptide under suitable culture conditions for the production of isoprene;   (b) removing a portion of the culture;   (c) filtering the removed portion of the culture to produce a permeate and a retentate;   (d) returning the retentate to the culture; and   (e) producing isoprene;   wherein the cultured cells undergoing steps (b), (c), and (d) either produce isoprene at a higher titer, or have greater average volumetric productivity of isoprene than the same cells cultured without undergoing steps (b), (c), and (d).