Abufalgha Ayman A, Curson Andrew R J, Lea-Smith David J, Pott Robert W M
Department of Process Engineering, Stellenbosch University, Banghoek Road, Stellenbosch, 7600, South Africa.
School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
Bioprocess Biosyst Eng. 2023 May;46(5):635-644. doi: 10.1007/s00449-023-02849-6. Epub 2023 Feb 9.
To design bioprocesses utilising hydrocarbon-metabolising organisms (HMO) as biocatalysts, the effect of the organism on the hydrodynamics of bubble column reactor (BCR), such as gas holdup, needs to be investigated. Therefore, this study investigates the first use of an HMO, Alcanivorax borkumensis SK2, as a solid phase in the operation and hydrodynamics of a BCR. The study investigated the gas holdup in 3-phase and 4-phase systems in a BCR under ranges of superficial gas velocities (U) from 1 to 3 cm/s, hydrocarbon (chain length C-) concentrations (H) of 0, 5, and 10% v/v and microbial concentrations (M) of 0, 0.35, 0.6 g/l. The results indicated that U was the most significant parameter, as gas holdup increases linearly with increasing U from 1 to 3 cm/s. Furthermore, the addition of hydrocarbons into the air-deionized water -SK2 system showed the highest increase in the gas holdup, particularly at high U (above 2 cm/s). The solids (yeast, cornflour, and SK2) phases had differing effects on gas holdup, potentially due to the difference in surface activity. In this work, SK2 addition caused a reduction in the fluid surface tension in the bioprocess which therefore resulted in an increase in the gas holdup in BCR. This work builds upon previous investigations in optimising the hydrodynamics for bubble column hydrocarbon bioprocesses for the application of alkane bioactivation.
为了设计以烃代谢微生物（HMO）作为生物催化剂的生物过程，需要研究该微生物对鼓泡塔反应器（BCR）流体动力学的影响，如气体滞留率。因此，本研究首次考察了HMO——阿尔坎ivorax borkumensis SK2在BCR操作和流体动力学中作为固相的情况。该研究考察了在1至3厘米/秒的表观气体流速（U）、0%、5%和10% v/v的烃（链长C-）浓度（H）以及0、0.35、0.6克/升的微生物浓度（M）范围内，BCR中三相和四相系统的气体滞留率。结果表明，U是最显著的参数，因为气体滞留率随U从1厘米/秒增加到3厘米/秒呈线性增加。此外，向空气-去离子水-SK2系统中添加烃后，气体滞留率增加最为显著，尤其是在高U（高于2厘米/秒）时。固体（酵母、玉米粉和SK2）相对气体滞留率有不同影响，这可能是由于表面活性的差异。在本研究中，添加SK2导致生物过程中流体表面张力降低，从而使BCR中的气体滞留率增加。这项工作建立在先前关于优化鼓泡塔烃生物过程流体动力学以应用烷烃生物活化的研究基础之上。
