Abstract

The study aims to optimize the medium composition for biobutanol production using a Palm Kernel Cake (PKC) hydrolysate by Clostridium saccharoperbutylacetonicum N1-4. Various nutrient factors affecting biobutanol production were screened using the Plackett-Burman design. These factors included: NH<inf>4</inf> NO<inf>3</inf>, KH<inf>2</inf> PO<inf>4</inf>, K<inf>2</inf> HPO<inf>4</inf>, MgSO<inf>4</inf>.7H<inf>2</inf> O, MnSO<inf>4</inf>.7H<inf>2</inf> O, FeSO<inf>4</inf>.7H<inf>2</inf> O, yeast extract, cysteine, PABA, biotin, and thiamin. The results were analyzed by an analysis of variance (ANOVA), which showed that cysteine (P=0.008), NH<inf>4</inf> NO<inf>3</inf> (P=0.011) dan yeast extract (P=0.036) had significant effects on biobutanol production. The established model from the ANOVA analysis had a significant value of P<inf>model</inf> >F = 0.0299 with an F-value of 32.82 which explains that the factors can explain in detail the variation in the data about the average and the interpretation is true with an R² value of 0.993. The estimated maximum biobutanol production was 10.56 g/L, whereas the optimized medium produced 15.49 g/L of biobutanol. Process optimizations with optimum concentration of cysteine, NH<inf>4</inf> NO<inf>3,</inf> and yeast extract have produced 21.33 g/L biobutanol which is a 37.7% improvement from the non-optimized medium. The findings show that PKC hydrolysate with the addition of optimal concentrations of the three types of medium namely, cysteine (0.15 g/L), NH<inf>4</inf> NO<inf>3</inf> (0.50 g/L), and yeast extract (1.5 g/L) during ABE fermentation, yielded a maximum biobutanol concentration of 21.33 g/L. Therefore, the results of this study provide good indications for promoting PKC hydrolysate as a new source of novel substrates with great potential in producing high biobutanol through ABE fermentation by C. saccharoperbutylacetonicum N1-4.