(528g) Optimization and Characterization of Candida Cylindracea Lipase Produced From Palm Kernel Cake By Solid-State Bioconversion

Lipases, (triacylglycerol acylhydrolase, EC.3.1.1.3) are one of the most important classes of industrial enzymes. The role of lipases is to hydrolyse triglycerides into diglycerides; monoglycerides, glycerol and fatty acids. Lipases from microbial sources are currently receiving particular attention due to of their potential applications in the industry, food technology and medicine. The high cost of enzyme production is still representing a challenge in large-scale industrial processes. To overcome this, the use of microorganisms along with agro-industrial residues such as palm kernel cake (PKC), which found in abundant amounts in Malaysia, as substrates to produce the enzyme could reduce the cost and contribute in adding value to low-cost material in the market.

This study was focused on the optimization of two factors and the characteristics of Candida cylindracea lipase for potential of applications through solid state bioconversion of palm kernel cake (PKC), a by-product of oil palm industry. A statistical design, face centred central composite design (FCCCD) was used to identify thirteen experiments to optimize two significant factors: yeast extract and inoculum. Fermentation was conducted in shake flasks employing solid-state fermentation for 72hrs at 30^°C and moisture content of 70.0%. As a result, a maximum lipase activity of 400.0±5.0 U/g dry PKC was achieved on PKC as basal medium supplemented with 2.5 (% w/v) of yeast extract, 2.0 (% v/w) Tween-80, 0.5 (%v/w) olive oil and inoculum concentration of 7.0 (%v/w) with average cell count of 2.0 Í10⁷ cells/ ml.  Analysis of variance (ANOVA) proved the significance of the model with R² value of 0.9893 at p< 0.05 which indicated a successful and a reliable design. The characteristics of lipase showed that the enzyme was stable for 24hrs at pH 7.0 and 8.0. On the other hand, the lipase produced retained its full activity at temperature ranges of 25-45^°C while 73% and 68% of the activity was retained at 50^°C and 55^°C respectively after 90 min of incubation. Development of this process should be conducted in the future for better lipase production and recovery at large scale.