화학공학소재연구정보센터
Chemical Engineering Research & Design, Vol.134, 80-89, 2018
An innovative bioprocess for methane conversion to methanol using an efficient methane transfer chamber coupled with an airlift bioreactor
Biosynthesis of methanol from methane as a direct method takes place at ambient temperature and pressure which causes a considerable reduction in process costs. In this study an efficient methane transfer chamber along with an external-loop airlift bioreactor were developed to dissolve methane and oxygen in the culture separately. Mass transfer coefficients for oxygen in the bioreactor and methane in the transfer chamber were obtained 97.2 h(-1) and 70.8 h(-1) respectively.TWo strains of methanotroph bacteria (AS1 and AS2) were also isolated from activated sludge. Factorial design of experiments for operational parameters showed a maximum productivity for AS1 strain at 28 degrees C when using nitrate as nitrogen source. Batch runs in airlift bioreactor using the AS1 strain and optimized operating parameters represented a peak of 1600 mg/L in methanol synthesis during the first 3:30 h without using inhibitor for methanol dehydrogenase (MDH) enzyme. Sequencing batch process, at the next step, was used to create intermediate lag phase and to increase the stability of microorganisms by forming flocs. The results of this study cleared that the designed system is safe and efficient to scale-up, and it can be considered as a potential alternative method in the production of methanol. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.