Single and multiplexed gene repression in solventogenic via Cas12a-based CRISPR interference.

The Gram-positive, spore-forming, obligate anaerobic firmicute species that make up the genus have broad feedstock consumption capabilities and produce value-added metabolic products, but genetic manipulation is difficult, limiting their broad appeal. CRISPR-Cas systems have recently been applied to species, primarily using Cas9 as a counterselection marker in conjunction with plasmid-based homologous recombination. CRISPR interference is a method that reduces gene expression of specific genes via precision targeting of a nuclease deficient Cas effector protein.