Parameswarappa Suneetha, Karigar Chandrakant, Nagenahalli Manjunath
Bioremediation Laboratory, Biochemistry Division, Department of Chemistry, Central College Campus, Bangalore University, Bangalore, Karnataka 560001, India.
Biodegradation. 2008 Feb;19(1):137-44. doi: 10.1007/s10532-007-9121-y. Epub 2007 May 30.
Pseudomonas fluorescens-CS2 metabolized ethylbenzene as the sole source of carbon and energy. The involvement of catechol as the hydroxylated intermediate during the biodegradation of ethylbenzene was established by TLC, HPLC and enzyme analysis. The specific activity of Catechol 2,3-dioxygenase in the cell free extracts of P. fluorescens-CS2 was determined to be 0.428 micromoles min(-1) mg(-1) protein. An aqueous-organic, Two-Phase Batch Culture System (TPBCS) was developed to overcome inhibition due to higher substrate concentrations. In TPBCS, P. fluorescens-CS2 demonstrated ethylbenzene utilization up to 50 mM without substrate inhibition on inclusion of n-decanol as the second phase. The rate of ethylbenzene metabolism in TPBCS was found enhance by fivefold in comparison with single phase system. Alternatively the alginate, agar and polyacrylamide matrix immobilized P. fluorescens-CS2 cells efficiently degraded ethylebenzene with enhanced efficiency compared to free cell cultures in single and two-phase systems. The cells entrapped in ployacrylamide and alginate were found to be stable and degradation efficient for a period of 42 days where as agar-entrapped P. fluorescens was stable and efficient a period of 36 days. This demonstrates that alginate and polyacrylamide matrices are more promising as compared to agar for cell immobilization.
荧光假单胞菌 - CS2 能够将乙苯作为唯一的碳源和能源进行代谢。通过薄层层析（TLC）、高效液相色谱（HPLC）和酶分析确定了儿茶酚作为乙苯生物降解过程中的羟基化中间体的参与情况。荧光假单胞菌 - CS2 无细胞提取物中儿茶酚 2,3 - 双加氧酶的比活性测定为 0.428 微摩尔·分钟⁻¹·毫克⁻¹ 蛋白质。为克服较高底物浓度引起的抑制作用，开发了一种水 - 有机双相分批培养系统（TPBCS）。在 TPBCS 中，荧光假单胞菌 - CS2 在加入正癸醇作为第二相时，能够利用高达 50 mM 的乙苯且无底物抑制作用。与单相系统相比，TPBCS 中乙苯的代谢速率提高了五倍。另外，与单相和双相系统中的游离细胞培养相比，藻酸盐、琼脂和聚丙烯酰胺基质固定化的荧光假单胞菌 - CS2 细胞能更有效地降解乙苯。发现包埋在聚丙烯酰胺和藻酸盐中的细胞在 42 天内保持稳定且降解效率高，而琼脂包埋的荧光假单胞菌在 36 天内保持稳定且高效。这表明与琼脂相比，藻酸盐和聚丙烯酰胺基质在细胞固定化方面更具前景。
