Prasertpornsakun Nattanun, Raita Marisa, Laosiripojana Navadol, Champreda Verawat
a The Joint Graduate School for Energy and Environment , King Mongkut's University of Technology Thonburi , Bangmod, Bangkok 10140 , Thailand.
b Enzyme Technology Laboratory , National Center for Genetic Engineering and Biotechnology , Khlong Luang , Pathum Thani 12120 , Thailand.
Biosci Biotechnol Biochem. 2015;79(11):1750-8. doi: 10.1080/09168451.2015.1056507. Epub 2015 Jun 24.
Enzymatic esterification is an efficient approach for modifying starch to functionalized biomaterials. In this study, conversion of cassava starch to fatty acid acyl esters using immobilized Thermomyces lanuginosus lipase on Fe3O4 microparticles modified with 3-aminopropyltriethoxysilane and covalently linked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide and N-hydroxysuccinimide (Fe3O4-AP-ED-lipase) in a solvent-free system was studied. An optimized reaction containing 5% w/v gelatinized starch, 1% v/v Triton X-100, and 1% w/v biocatalyst with 2.5% w/v of fatty acids (palmitic, oleic, or linoleic acid) resulted in esterified products with a degree of substitution (DS) of 0.12-0.14, while a slightly lower DS was observed using crude palm fatty acid distillate as the acyl donor with 42.9-59.6% recovery yield. Increasing DS led to lower glass transition temperature and higher viscosity of the esterified products. The enzyme showed high operational stability with 85% retaining in activity after recycling in three consecutive batches with simple separation by magnetization, leading to improved process economics.
酶促酯化是一种将淀粉改性为功能化生物材料的有效方法。在本研究中，研究了在无溶剂体系中，使用固定在经3-氨丙基三乙氧基硅烷改性并通过1-乙基-3-(3-二甲氨基丙基)碳二亚胺和N-羟基琥珀酰亚胺共价连接的Fe3O4微粒上的嗜热栖热菌脂肪酶，将木薯淀粉转化为脂肪酸酰基酯（Fe3O4-AP-ED-脂肪酶）。一个优化的反应包含5% w/v糊化淀粉、1% v/v Triton X-100和1% w/v生物催化剂以及2.5% w/v脂肪酸（棕榈酸、油酸或亚油酸），得到取代度（DS）为0.12 - 0.14的酯化产物，而以粗棕榈脂肪酸馏出物作为酰基供体时观察到的DS略低，回收率为42.9 - 59.6%。取代度增加导致酯化产物的玻璃化转变温度降低和粘度升高。该酶表现出高操作稳定性，通过简单的磁分离在连续三个批次中循环后仍保留85%的活性，从而提高了工艺经济性。
