Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS, Université de Sfax, route de Soukra, BPW 1173 Sfax-Tunisia.
BMC Biotechnol. 2011 Jun 17;11:68. doi: 10.1186/1472-6750-11-68.
Waxes are esters of long-chain fatty acids and long-chain alcohols. Their principal natural sources are animals (sperm whale oil) and vegetables (jojoba) which are expensive and not easily available. Wax esters synthesized by enzymatic transesterification, using palm stearin as raw material, can be considered as an alternative to natural ones.
Palm stearin is a solid fraction obtained by fractionation of palm oil. Palm stearin was esterified with cetyl alcohol to produce a mixture of wax esters. A non-commercial immobilized lipase from Rhizopus oryzae was used as biocatalyst. Response surface methodology was employed to determine the effects of the temperature (30-50 °C), the enzyme concentration (33.34-300 IU/mL), the alcohol/palm stearin molar ratio (3-7 mol/mol) and the substrate concentration (0.06-0.34 g/mL) on the conversion yield of palm stearin. Under optimal conditions (temperature, 30 °C; enzyme concentration, 300 IU/mL; molar ratio 3 and substrate concentration 0.21 g/mL) a high conversion yield of 98.52% was reached within a reaction time of 2 h.
Response surface methodology was successfully applied to determine the optimum operational conditions for synthesis of palm stearin based wax esters. This study may provide useful tools to develop economical and efficient processes for the synthesis of wax esters.
蜡酯是长链脂肪酸和长链醇的酯。它们的主要天然来源是动物（抹香鲸油）和植物（霍霍巴），这些来源既昂贵又不易获得。使用棕榈硬脂作为原料，通过酶转酯化合成的蜡酯可以被视为天然蜡酯的替代品。
棕榈硬脂是从棕榈油分馏得到的固体部分。棕榈硬脂与十六醇酯化生成蜡酯混合物。使用非商业固定化米根霉脂肪酶作为生物催化剂。采用响应面法确定温度（30-50°C）、酶浓度（33.34-300IU/mL）、醇/棕榈硬脂摩尔比（3-7mol/mol）和底物浓度（0.06-0.34g/mL）对棕榈硬脂转化率的影响。在最佳条件下（温度 30°C；酶浓度 300IU/mL；摩尔比 3 和底物浓度 0.21g/mL），在 2h 的反应时间内达到了 98.52%的高转化率。
响应面法成功地应用于确定基于棕榈硬脂的蜡酯合成的最佳操作条件。本研究可为开发经济高效的蜡酯合成工艺提供有用的工具。
