Optimization of the microbial synthesis of dihydroxyacetone from glycerol with Gluconobacter oxydans.
An optimized repeated-fed-batch fermentation process for the synthesis of dihydroxyacetone (DHA) from glycerol utilizing Gluconobacter oxydans is presented. Cleaning, sterilization, and inoculation procedures could be reduced significantly compared to the conventional fed-batch process. A stringent requirement was that the product concentration was kept below a critical threshold level at all times in order to avoid irreversible product inhibition of the cells. On the basis of experimentally validated model calculations, a threshold value of about 60 kg x m(-3) DHA was obtained. The innovative bioreactor system consisted of a stirred tank reactor combined with a packed trickle-bed column. In the packed column, active cells could be retained by in situ immobilization on a hydrophilized Ralu-ring carrier material. Within 17 days, the productivity of the process could be increased by 75% to about 2.8 kg x m(-3) h(-1). However, it was observed that the maximum achievable productivity had not been reached yet.
Institute of Chemical Engineering, Munich University of Technology, Boltzmannstrasse 15, 85747 Garching, Germany. hekmat@lrz.tum.de
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D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D002455:Cell Division / Q000502:physiology; D003198:Computer Simulation; D004098:Dihydroxyacetone / Q000096:biosynthesis*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D020600:Gluconobacter oxydans / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D007700:Kinetics; D008954:Models, Biological; D010865:Pilot Projects; D011786:Quality Control
D004098:Dihydroxyacetone; D005990:Glycerol