Verbesserung der Y-Werte bei Wachstum von Hansenula polymorpha auf Methanol durch simultane verwertung von Glucose

The simultaneous utilization of methanol and glucose by Hansenula polymorpha MH20 was investigated in chemostat (C-limited) cultivation. The mixed-substrate utilization results in biomass yields which are greater up to 20 to 25% as expected assuming an additive growth on both substrates. This is referred to as an auxiliary-substrate effect. Additionally, methanol can be utilized at higher growth rates in the presence of glucose compared to those obtained on this substrate alone. The extend of the auxiliary-substrate effect and the optimum ratio of substrates to reach this effect depend on dilution rate. The greatest stimulation in yield is obtained at D ∼ 0.1 h−1, after raising the dilution rate this effect diminishes. At a rate of 0.1 h−1 the optimum mixed-substrate ratio of methanol: glucose is 7: 1(g). By increasing the growth rate the ratio changes toward glucose and reached a value of 1:1 (g) at D = 0.3 h−1. This change in the optimum ratio correlates with diminution in yield coefficient of methanolp accomanying an increase in growth rate > 0.15 h−1. Energy balances of the utilization of the single substrates are used for interpretation of these results. From this it is evident that methanol does not play the role of an energy-rich substrate in the metabolism of yeast. Rather glucose is the energy-providing substrate in this combination.

[1]  J. Roels.  Application of macroscopic principles to microbial metabolism. , 1980, Biotechnology and bioengineering.

[2]  T. Egli,et al.  Regulatory flexibility of methylotrophic yeasts in chemostat cultures: Simultaneous assimilation of glucose and methanol at a fixed dilution rate , 1982, Archives of Microbiology.

[3]  H. Sahm,et al.  Regulation of alcohol oxidase synthesis in Hansenula polymorpha: Oversynthesis during growth on mixed substrates and induction by methanol , 1980, Archives of Microbiology.

[4]  T. Bley,et al.  Theoretische Bestimmung energetischer Wirkungsgrade der mikrobiellen Kohlenstoffsubstratwandlung und Vergleich mit experimentellen Werten an Phasenkulturen , 1982 .

[5]  T. Bley,et al.  [Theoretical determination of the energy efficiency of microbial carbon substrate conversion and comparison with experimental values in phase cultures]. , 1982, Zeitschrift fur allgemeine Mikrobiologie.

[6]  T. Egli.  Wachstum von Methanol assimilierenden Hefen , 1980 .

[7]  W. Babel.  Mischsubstratfermentation – ein energetisch begründetes Konzept , 1980 .

[8]  W. Babel.  Bewertung von Substraten für das mikrobielle Wachstum auf der Grundlage ihres Kohlenstoff/Energie-Verhältnisses† , 1979 .

[9]  W. Babel.  [Evaluation of substrates for microbial growth on the basis of their carbon/energy ratio]. , 1979, Zeitschrift fur allgemeine Mikrobiologie.

[10]  J. Rokem,et al.  Maintenance requirements for bacteria growing on C1‐compounds , 1978, Biotechnology and bioengineering.

[11]  J. Linton,et al.  A preliminary study on growth yields in relation to the carbon and energy content of various organic growth substrates , 1978 .

[12]  C. Anthony.  The Prediction of Growth Yields in Methylotrophs , 1978 .

[13]  A. Ben-Bassat,et al.  Bacterial yields on methanol, methylamine, formaldehyde, and formate , 1976, Biotechnology and bioengineering.

[14]  H. Asthana,et al.  Growth of yeast on methanol as the sole carbon substrate , 1971 .