摘要
用吸附法将甲烷菌整细胞固定在某些有机和无机载体上,制备了丙烯环氧化反应的固定化生物催化剂。不同载体对固定化细胞的催化活性有很大影响,用一填充床流动反应器对吸附在不同载体上的固定化细胞进行了活性考察。结果表明:用有机的疏水载体如聚丙烯,石蜡等制成的固定化细胞具有较高的环氧化催化活性,且不同载体制成的固定化细胞的催化活性大致相同,约在28nmol/mg cell。用无机亲水类载体制成的固定化细胞,其环氧化催化活性差别很大,且大多数这类载体均比有机的疏水载体活性低,但用特殊方法处理过的砂子为载体制成的固定化细胞,其催化活性很高。还发现,用3AK型分子筛和酸处理过的Al_2O_3和3AK型分子筛为载体时,固定化细胞的活性与载体表面酸性有一定关系。
The direct insertion of molecular oxygen into organic compounds is an example of a type of reaction which is carried out in a wide variety of living organisms, including many microbial cell lines. The reactions are catalysed by mono-oxygenases to produce epoxides from alkenes. Numerous studies have been carried out on the bio-catalytic activity of methanotrophic bacteria and microbacterium for this kind of reactions.
Some results have been obtained from immobilized cells adsorbed on glass beads and sand as the biocatalysts for propylene epoxidation reaction.
In this paper both hydrophobic and hydrophilic supports were used for methanomonas GY-J-3 cell immobilization. Experimental results show that the immobilized cells adsorbed on pretreated sand were more active than the one adsorbed on other supports for propylene epoxidation reaction. Hydrophobic materials, such as polypropylene, paraffin, were better than most of hydrophilic materials, such as Al2O3, clay, as the supports for cell adsorption immobilization. The propylene epoxidation activity was measured in a continuous flow packed-bed type bioreactor. The products were analyzed by gas chromatography. The yield of propylene oxide for biocatalysts immobilized on organic supports and pretreated sand as well as zeolite, is about 28 nmol/mg cell during the period of 5 h.
The surface acidic properties of inorganic supports, Al2O3 and zeolite, were studied by means of infrared spectra following pyridine adsorption. The results show that the Lewis acidity of the supports influences the biocatalytic activity of the immobilized cells.
出处
《分子催化》
EI
CAS
CSCD
1991年第3期227-232,共6页
Journal of Molecular Catalysis(China)
基金
中国石化总公司资助
