Michel F C, Grulke E A, Reddy C A
Department of Chemical Engineering, Michigan State University, East Lansing 48824-1101.
Appl Environ Microbiol. 1992 May;58(5):1740-5. doi: 10.1128/aem.58.5.1740-1745.1992.
In mycelial pellet cultures of the white rot basidiomycete Phanerochaete chrysosporium, low oxygen concentration negatively affects the production of the extracellular lignin peroxidases and manganese peroxidases which are key components of the lignin-degrading system of this organism. To test the hypothesis that oxygen limitation in the pellets is responsible for this effect, oxygen microelectrodes were used to determine oxygen concentration gradients within the mycelial pellets of P. chrysosporium. Pellets were removed from oxygenated cultures, allowed to equilibrate with air, and probed with oxygen microelectrodes. The oxygen profiles were modelled assuming that O2 uptake follows a Michaelis-Menten relationship. The Vmax and Km values for oxygen uptake were 0.76 +/- 0.10 g/m3 of pellet per s and 0.5 +/- 0.3 g/m3, respectively. These kinetic values were used to predict respiration rates in air-flushed cultures, oxygen-flushed cultures, and cultures with large pellets (diameter greater than 6 mm). The predicted respiration rates were independently validated by experimentally measuring the evolution of carbon dioxide from whole cultures.
在白腐担子菌黄孢原毛平革菌的菌丝球培养物中，低氧浓度会对细胞外木质素过氧化物酶和锰过氧化物酶的产生产生负面影响，而这两种酶是该生物体木质素降解系统的关键组成部分。为了验证菌丝球中的氧限制是造成这种影响的原因这一假设，使用氧微电极来测定黄孢原毛平革菌菌丝球内的氧浓度梯度。将菌丝球从充氧培养物中取出，使其与空气平衡，然后用氧微电极进行探测。假设氧气摄取遵循米氏关系对氧分布进行建模。氧气摄取的Vmax和Km值分别为每秒每立方米菌丝球0.76±0.10克和0.5±0.3克/立方米。这些动力学值用于预测在空气冲洗培养物、氧气冲洗培养物和大菌丝球（直径大于6毫米）培养物中的呼吸速率。通过实验测量整个培养物中二氧化碳的释放，对预测的呼吸速率进行了独立验证。
