Production of ferulic acid from oil palm frond bagasse hydrolysis using mixed culture fermentation
Ferulic acid (FA) production has become a frequent focus on today’s research due to its antioxidant properties. Enzymatic hydrolysis stands as one of the most efficient method in producing FA. Bacteria and fungi proved to be crucial in enzymatic hydrolysis of FA as they possess the ability to releas...
| Summary: | Ferulic acid (FA) production has become a frequent focus on today’s research due to its antioxidant properties. Enzymatic hydrolysis stands as one of the most efficient method in producing FA. Bacteria and fungi proved to be crucial in enzymatic hydrolysis of FA as they possess the ability to release ferulic acid esterase (FAE). However, there has been little to none studies reported on the usage of mixed culture as inoculum. In this study, an appropriate mixed culture fermentation approach using oil palm frond bagasse (OPFB) as substrate was applied for FA production improvement. Mixed culture was obtained from soil of a palm oil plantation. The mixed culture was acclimatized with OPFB substrate before being used in the research. The content of this mixed culture was identified to determine the microorganisms that contributed to the FA production. Two bacteria were discovered to be affecting FA production which were Bacillus cereus CCM 2010 and B. thuringiensis ATCC 10792. Both bacteria are reported to possess the ability to release FAE. The FA production was achieved using submerged fermentation. The enzymatic hydrolysis of FA took place during this process. Samples were analysed using High-Performance Liquid Chromatography (HPLC) to determine the FA content. Optimization of FA production using mixed culture was carried out with response surface methodology. The optimum condition for FA production from OPFB using mixed culture was determined to be at 26°C of temperature, pH value at 9, 150 rpm of agitation speed, 1-day of response time and 2% of inoculum volume. The optimum value of FA produced was 205.724 mg FA/kg OPFB with an error of 8.413%. Kinetic study was conducted as the next step with Michaelis-Menten kinetic model used as a reference kinetic equation. Three kinetic constants, Vmax, Km and Ks were determined as 3.725 x 10-3 gL-1h-1, 28.231 gL-1 and 0.013 h-1 respectively using Runge-Kutta Fourth Order approach. The FAE mechanism was also studied in the next step of the process. Maximum FAE activity was achieved at the 28-hour of fermentation process at 3.7 x 10-3 mU/mL. This result proved that enzymatic hydrolysis occurred during fermentation process. This finding is aligned with other studies that suggested enzymatic hydrolysis was responsible for the OPFB cell wall breakdown during FA production. The outcome of this study suggest that the usage of mixed culture has the potential to induce enzymatic hydrolysis hence improving FA production from OPFB during fermentation process. |
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