Optimisation and Characterisation of Lipase-Catalysed Synthesis of a Kojic Monooleate Ester in a Solvent-Free System by Response Surface Methodology

Abstract

Kojic acid is widely used to inhibit the browning effect of tyrosinase in cosmetic and food industries. In this work, synthesis of kojic monooleate ester (KMO) was carried out using lipase-catalysed esterification of kojic acid and oleic acid in a solvent-free system. Response Surface Methodology (RSM) based on central composite rotatable design (CCRD) was used to optimise the main important reaction variables, such as enzyme amount, reaction temperature, substrate molar ratio, and reaction time along with immobilised lipase from Candida Antarctica (Novozym 435) as a biocatalyst. The RSM data indicated that the reaction temperature was less significant in comparison to other factors for the production of a KMO ester. By using this statistical analysis, a quadratic model was developed in order to correlate the preparation variable to the response (reaction yield). The optimum conditions for the enzymatic synthesis of KMO were as follows: an enzyme amount of 2.0 wt%, reaction temperature of 83.69°C, substrate molar ratio of 1:2.37 (mmole kojic acid:oleic acid) and a reaction time of 300.0 min. Under these conditions, the actual yield percentage obtained was 42.09%, which is comparably well with the maximum predicted value of 44.46%. Under the optimal conditions, Novozym 435 could be reused for 5 cycles for KMO production percentage yield of at least 40%. The results demonstrated that statistical analysis using RSM can be used efficiently to optimise the production of a KMO ester. Moreover, the optimum conditions obtained can be applied to scale-up the process and minimise the cost.

Development of a kojic monooleate-enriched oil-in-water nanoemulsion as a potential carrier for hyperpigmentation treatment

“…KMO was obtained according to the method used by Jumbri et al 11 Virgin coconut oil (VCO, from Cocos nucifera), soybean oil (SO), safflower seed oil (SSO), castor oil (CO), xanthan gum (from Xanthomonas campestris), and potassium sorbate were purchased from Sigma-Aldrich (St Louis, MO, USA). Palm kernel oil ester (PKOE) was obtained according to the method used by Keng et al 12 Lemon essential oil (LO) South African was purchased from Wellness Original Ingredient (Puchong, Malaysia), whereas polyoxyethylene sorbitan monooleate and Tween 80 (hydrophile-lipophile balance [HLB] 15.0) were purchased from EMD Millipore (Billerica, MA, USA).…”

Optimization and characterization of magnetite–reduced graphene oxide nanocomposites for demulsification of crude oil in water emulsion

“…According to Jumbri et al, a positive sign implies a synergistic effect, and a negative sign implies an antagonistic effect. 26 A coefficient with negative values demonstrates a negative inuence of parameters on the reaction yield. Fig.…”

Evaluation of Direct Esterification of Fatty Acid Derivative of Kojic Acid in Co-solvent System: A Statistical Approach

“…From the Figure 2C the enzyme amount of 3.00 wt% and a moderate temperature at 80°C appeared to be a favorable condition for the esterification reaction. This phenomenon is related to the active site of enzyme molecules, where the large excess of enzyme cannot be exposed to the substrates due to possible protein aggregation and hence, reducing the conversion of yield [20]. The esterification activity becomes slow as temperature increases more than 80°C at a high amount of enzymes due to the inactivation of the enzyme at a high temperature ( Figure 2D).…”