3.3. Batch fermentation
ABE fermentation of enzymatic hydrolysates of C. forskohlii roots (glucose equivalent to 31.46 g/l) was performed by using C. acetobutyllicum NCIM 2877. It was found that fermentation could produce only 0.55 g/l of total solvents and 4.29 g/l of total acids as compared to 6.95 g/l of total solvents and 1.59 g/l of total acids in the control production medium containing only glucose. The concentration of probable inhibitors i.e. phenolic compounds in root hydrolysates may be a possible reason for the low production of solvent. C. forskohlii Briq is a herbal plant belonging to the Lamiaceae family. This plant is known to contain higher phenolic contents as compared to other Lamiaceae species. The plant extract with higher phenolic compounds are reported to be antimicrobial [41]. Other investigators have also reported the extracts from these plants to be rich in phenolic compounds [42]. After extraction of forskolin, these phenolic compounds might remain in the roots which could be