Moreira M T, Sanromán A, Feijoo G, Lema J M
Dept. of Chemical Engineering, University of Santiago de Compostela, Spain.
Enzyme Microb Technol. 1996 Sep;19(4):261-6. doi: 10.1016/0141-0229(95)00244-8.
The application of a pulsing flow to fluidized-bed bioreactors in order to control pellet morphology of filamentous fungi was investigated. The operation at an optimum pulsation frequency allowed two effects: a narrower pellet size distribution which improves fluidization quality, and an enhanced production of citric acid by Aspergillus niger and manganese peroxidase by Phanerochaete chrysosporium. In the case of A. niger, the pellet diameter corresponding to the pulsed system operated at 0.35 s-1 was kept between 3.3 +/- 0.1 mm after 22 days of operation; however, in the nonpulsed bioreactor which was operative for only 11 days, pellets with a diameter of 6.7 +/- 0.3 mm were produced. Similar results were obtained in the case of P. chrysosporium, since with a pulsing frequency of 0.0625 s-1, a pellet diameter of 2.1 +/- 0.4 mm after 34 days of operation was maintained. On the contrary, the system without pulsation presented great conglomerates of mycelia with an average diameter of 3 cm surrounded by free pellets with a diameter distribution of 2.75 +/- 0.5 mm. The nonpulsed bioreactor was only operative for 14 days. Both citric acid and manganese peroxidase production attained higher values and were maintained longer in the pulsed bioreactor.
研究了将脉冲流应用于流化床生物反应器以控制丝状真菌菌球形态的情况。在最佳脉动频率下运行有两个效果：更窄的菌球尺寸分布，这改善了流化质量；黑曲霉柠檬酸产量增加，黄孢原毛平革菌锰过氧化物酶产量增加。对于黑曲霉，在0.35 s-1运行的脉冲系统中，运行22天后，菌球直径保持在3.3±0.1 mm之间；然而，在仅运行11天的非脉冲生物反应器中，产生了直径为6.7±0.3 mm的菌球。对于黄孢原毛平革菌也得到了类似的结果，因为在脉动频率为0.0625 s-1时，运行34天后菌球直径保持在2.1±0.4 mm。相反，无脉动系统呈现出平均直径为3 cm的大菌丝团块，周围是直径分布为2.75±0.5 mm的游离菌球。非脉冲生物反应器仅运行了14天。在脉冲生物反应器中，柠檬酸和锰过氧化物酶的产量都达到了更高的值，并且维持时间更长。
