caa a22 4500 465822185 CHVBK 20180323112138.0 cr unu---uuuuu 170327e19900301xx s 000 0 eng 10.1007/BF00164742 doi (NATIONALLICENCE)springer-10.1007/BF00164742 Methanol-dependent production of dihydroxyacetone and glycerol by mutants of the methylotrophic yeast Hansenula polymorpha blocked in dihydroxyacetone kinase and glycerol kinase [Elektronische Daten] [W. de Koning, R. Weusthuis, W. Harder, L. Dijkhuizen] Summary: Various factors controlling dihydroxyacetone (DHA) and glycerol production from methanol by resting cell suspensions of a mutant of Hansenula polymorpha, blocked in DHA kinase and glycerol kinase, were investigated. The presence of methanol (250mM) and an additional substrate (0.5%, w/v) to replenish the xylulose-5-phosphate required for the assimilation reaction (DHA synthase) was essential for significant triose production by this double mutant. A number of sugars were tested as additional substrates and C5 sugars gave the highest triose accumulation (ca. 20mM after 45h). Glucose was the poorest additional substrate and triose production only started after its exhaustion, which occurred in the first few hours. Other sugars were metabolized at a much lower rate and accumulation of trioses began right at the start of the experiments and gradually increased with time. The production rate of total trioses increased, and the relative amount of glycerol diminished with higher oxygen supply rates. The data suggest that conversion of DHA into glycerol, catalysed by reduced nicotine adenine dinucleotide (NADH)-dependent DHA reductase, is partly regulated via intracellular NADH levels. Further support for this hypothesis was obtained in experiments with antimycin A, an inhibitor of the electron transport chain. Addition of higher amounts of methanol and xylose, either by increasing the initial concentrations or by repeated addition of these substrates, resulted in considerably enhanced productivity and a switch towards glycerol formation. After reaching a level of approximately 25mM the DHA concentration remained constant while the glycerol level gradually increased with time. After an incubation period of 350 h, a total of 3.9 M methanol and 0.62 M xylose had been converted, which resulted in accumulation of 0.76 M trioses, mostly glycerol. Springer-Verlag, 1990 de Koning W. Department of Microbiology, University of Groningen, Kerklaan 30, NL-9751 NN, Haren, The Netherlands aut Weusthuis R. Department of Microbiology, University of Groningen, Kerklaan 30, NL-9751 NN, Haren, The Netherlands aut Harder W. Department of Microbiology, University of Groningen, Kerklaan 30, NL-9751 NN, Haren, The Netherlands aut Dijkhuizen L. Department of Microbiology, University of Groningen, Kerklaan 30, NL-9751 NN, Haren, The Netherlands aut Applied Microbiology and Biotechnology Springer-Verlag 32/6(1990-03-01), 693-698 0175-7598 32:6<693 1990 32 253 https://doi.org/10.1007/BF00164742 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00164742 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- de Koning W. Department of Microbiology, University of Groningen, Kerklaan 30, NL-9751 NN, Haren, The Netherlands aut NATIONALLICENCE 700 1- Weusthuis R. Department of Microbiology, University of Groningen, Kerklaan 30, NL-9751 NN, Haren, The Netherlands aut NATIONALLICENCE 700 1- Harder W. Department of Microbiology, University of Groningen, Kerklaan 30, NL-9751 NN, Haren, The Netherlands aut NATIONALLICENCE 700 1- Dijkhuizen L. Department of Microbiology, University of Groningen, Kerklaan 30, NL-9751 NN, Haren, The Netherlands aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer-Verlag 32/6(1990-03-01), 693-698 0175-7598 32:6<693 1990 32 253 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer