Rawool S B, Sahoo S, Rao K K, Sureshkumar G K
Biochemical Engineering Group, Department of Chemical Engineering, and Biotechnology Centre, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India.
Biotechnol Prog. 2001 Sep-Oct;17(5):832-7. doi: 10.1021/bp010078z.
Cultivations of Aspergillus niger cells in which oxygen was provided through the liquid-phase oxygen supply strategy (which involves the need-based decomposition of H2O2 pulses to yield the necessary oxygen) were studied. Concentrations of H2O2 in the range of 1 to 5 mM were found to be suitable for use in cultivations. The growth rate constant of 0.17 h(-1) obtained in the H2O2-based cultivation, was comparable to that obtained in the cultivation with aeration; however, the maximum cell concentration in the H2O2-based cultivation was 124% of that obtained in cultivation with aeration. Maximum concentrations of catalase, protease and glucose oxidase obtained in the H2O2-based cultivation, were 240%, 172%, and 124% respectively, of those obtained in the cultivation with aeration. Further, the specific enzyme levels (units per gram cell) of catalase and protease obtained in the H2O2-based cultivation were 172% and 156% of those obtained in the cultivation with aeration, whereas, the specific glucose oxidase levels were comparable. In addition, the oxygen profiles inside the pellets ofA. niger during both the modes of oxygen supply were described using mathematical models. Studies to elucidate the mechanism of oxygen availability showed that the decomposition of the H2O2 supplied in the extracellular space occurred intracellularly, as well as extracellularly, to yield oxygen. Also, the proton motive force (PMF) was found to be involved in the process of oxygen availability from H2O2 to A. niger cells.
研究了黑曲霉细胞的培养，其中通过液相供氧策略（涉及基于需求分解H2O2脉冲以产生所需氧气）提供氧气。发现1至5 mM范围内的H2O2浓度适用于培养。在基于H2O2的培养中获得的0.17 h(-1)的生长速率常数与通气培养中获得的相当；然而，基于H2O2的培养中的最大细胞浓度是通气培养中获得的最大细胞浓度的124%。在基于H2O2的培养中获得的过氧化氢酶、蛋白酶和葡萄糖氧化酶的最大浓度分别是通气培养中获得的最大浓度的240%、172%和124%。此外，基于H2O2的培养中获得的过氧化氢酶和蛋白酶的比酶水平（每克细胞的单位）分别是通气培养中获得的比酶水平的172%和156%，而比葡萄糖氧化酶水平相当。此外，使用数学模型描述了两种供氧模式下黑曲霉颗粒内部的氧气分布。阐明氧气可利用性机制的研究表明，细胞外空间中供应的H2O2的分解在细胞内和细胞外均发生以产生氧气。此外，发现质子动力势（PMF）参与了从H2O2到黑曲霉细胞的氧气可利用过程。
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