Whereas the gene stability related considerations are important in bioprocessing with recombinant cultures, bioreactor design and scale-up require attention to the often reduced shear tolerance of the genetically altered biocatalysts relative to the corresponding wild strains. In addition, the peculiarities of expression of the rDNA product impact the downstream recovery methods. As a consequence, a bioprocessing scheme and the process machinery designed for a naturally occurring organism may need significant modifications for use with a genetically modified variety of the same organism. The case studies described highlight some of the processing constraints and consideration of general relevance.