新型光交联聚氨酯固定化细胞载体的研究

STUDIES ON A NEW PHOTO-CROSSLINKED POLYURETHANE AS THE CARRIER OF IMMOBILIZED CELLS

本文主要研究新型光交联聚氨酯固定化载体PCPUM的交联、结构与固定化细胞的性能。结果表明:PCPUM能在室温短时光照的温和条件下交联并包埋枯草杆菌,得到固定化细胞,其产生α-淀粉酶的能力比游离细胞高30％左右,且对温度和pH的适应性比游离细胞增强;改变预聚物组成、分子量、浓度等条件,可引起载体比表面、孔容、孔径、亲疏水性等的变化,从而影响固定化细胞的产酶性能、漏菌程度和使用寿命;电镜观察发现细胞主要存在于载体孔隙内,载体表层的细胞密度较大。

The crosslinking, structure and properties of a new carrier of immobilized cells, the photo-crosslinked polyurethane PCPUM, were studied. The prepolymer of PCPUM can be crosslinked and used to entrap the Bacillus Substilis living cells to form the immobilized cells by irradiating with UV-light at room temperature for a short time. The a-amylase activity of the PCPUM immobilized cells is about 30% higher than that of free cells at same conditions. Their adaptabilities to temperature and pH are also better than that of the free cells. The volume of pores, average diameter of pores and specific surface of the carrier have remarkable effects on the a-amylase activity and the leakage of the cells of the immobilized cells, and these parameters of the carrier can be controlled by changing the compositions, tho average molecular weights and concentrations of the prepolymers as well as the thickness of the carrier. Electron micrographs indicated the cells exist domina-tely in the pores of the PCPUM carrier, and near the surface of the carrier, the density of the cells is larger than inside the cerrier.