ISSN:
0006-3592
Keywords:
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
The cultural properties of an obligate methanol utilizer, Methylomonas methanolovorans, were investigated in batch and continuous cultures, and the problems of mass-energy balances were examined. Among the culture data, an exponential increase of growth lag with increased methanol concentration, as well as the inhibition kinetics in the relation between attainable maximum specific growth rate (μm ≦ 0.52) and methanol concentration are of interest. In the latter case, the inhibition constant (Ki) and the index number were 40 g/L, and 3 (dimensionless), respectively. The maximum yield coefficient (Y) in both batch and chemostat cultures was around 0.52. An analysis of the behavior of respiratory activity (Qo2) in response to the dissolved oxygen concentration (DO) indicated that the oxygen-terminal entity should be regarded as a single one with a saturation constant for DO of 32 μg/L (1.1 × 10-6M). Chemostat data showed that the saturation constant for methanol is as low as 2.2 mg/L or 7 × 10minus;5M. A linear relationship was observed between the respiratory activity (mol O2g-1h-1) and the specific growth rate (μ i h-1), with the relationship Qo2 = 0.0504μ + 0.00112. The theory of mass and energy balances used by Roels has been reformed to give useful relationships between RQ or the cell yield and μ. In the case of M. methanolovorans, the relations can be greatly simplified since the influence of metabolic by-product formation was negligible. Experimental RQ values (theoretical values for Y = 0.52 and 0.445) at varying μ-values were compared with theoretical ones; despite considerable fluctuations, the results were regarded to conform with theory. By use of mass balance equations and enthalpy data of known compounds, the heat evolution in methanol fermentation was estimated indirectly to be 612 kcal/100 g biomass formed. The YATP problems are also discussed.
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bit.260251116
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