Investigation of the substrate and energy metabolism of methanol utilizing bacteria, Methylomonas L3, under dynamic and steady state conditions

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5492628

Coskuner, Y T

The dynamic and steady state behavior of the ribulose monophosphate type Methylomonas L3-an obligate methylotroph-in batch and continuous cultures were investigated in terms of bioenergetics. It was observed that the exponential growth phase in batch cultures was made up of several subdivided exponential phases which were also comprised of: (1) An energy production phase (carbon dissimilation) (2) An intracellular formaldehyde regulation phase (formaldehyde discharging) (3) An energy utilization phase (carbon assimilation). In their effort to reduce effects of the excess formaldehyde Methylomonas L3 employed the cyclic pathway at steady states with high residual substrate (methanol) concentration. Due to this metabolic change the substrate was mostly oxidized to carbon dioxide so that low biomass yields resulted. The adenylate energy charge findings indicated an energy problem due increased maintenance processes such as methanol transport, formaldehyde regulation, and excess formaldehyde oxidation by the cyclic pathway at steady state with high residual substrate concentration. These significant changes in the cellular metabolism explained the system behavior at unstable steady states when feed substrate is high enough and/or a control algorithm was employed. The nonlinear effects of conventional, linear, proportional-integral-derivation (PID) feedback controller on the system were also experimentally shown. Numerous steady states were found to be possible at a given dilution rate and feed substrate concentration depending on the culture history. The location of the steady states was found to fall on a straight line in the cell density-residual substrate concentration phase diagram.

• Research Organization: Worcester Polytechnic Inst., MA (USA)
• OSTI ID: 5492628
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
090222* -- Alcohol Fuels-- Preparation from Wastes or Biomass-- (1976-1989)
140504 -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989)
ALCOHOLS
ALDEHYDES
ALGORITHMS
BACTERIA
BATCH CULTURE
BIOCHEMICAL REACTION KINETICS
BIOCONVERSION
BIOMASS
BIOREACTORS
BIOSYNTHESIS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CONTINUOUS CULTURE
CONTROL
ENERGY SOURCES
FORMALDEHYDE
HYDROXY COMPOUNDS
KINETICS
MATHEMATICAL LOGIC
METABOLISM
METHANOL
MICROORGANISMS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PROCESS CONTROL
REACTION KINETICS
RENEWABLE ENERGY SOURCES
STEADY-STATE CONDITIONS
SYNTHESIS