Limitations of Cloning in Industrial Strains - In many industrial strains, cloning is difficult due to non availability of

(i) suitable vectors and

(ii) methods for introduction of exogenous DNA. Even after successful transfer, stable propagation of cloned genes is problematic as observed in Bacillus subtilis. This is due to rearrangement, deletion and cleavage of cloned sequences and the plasmid vector carrying it.

However, several genes for metabolism have been cloned from Clostridium acetobutylicum and the technology for their integration in B. subtilis is being optimized and standardized. C. acetobutylicum is used for the biological production of acetone and butanol