Jean-Pierre Belaich

Energetics of the growth of Methanococcus thermolithotrophicus

Methanococcus thermolithotrophicus was grown in a mineral salts medium at 65° C in a fermenter gassed with H2 and CO2, which were the sole carbon and energy sources. Evolution of growth parameters during batch culture experiments showed the existence of an uncoupling phenomenon. The growth was then studied using a continuous technique and steady states for various gas flow rates were obtained. YCH4and the maintenance coefficient varied with the gas input. The maximum YCH4 determined for Methanococcus thermolithotrophicus was 3.33 g·mol-1 CH4. An excess of energy and carbon sources induced uncoupling of growth.

Energetics of the growth of Methanobacterium thermoautotrophicum and Methanococcus thermolithotrophicus on ammonium chloride and dinitrogen

AbstractMethanobacterium thermoautotrophicum was grown in continuous culture in a fermenter gassed with H2 and CO2 as sole carbon and energy sources, and in a medium which contained either NH4Cl or gaseous N2 as nitrogen source. Growth was possible with N2. Steady states were obtained at various gas flow rates with NH4Cl and with

Crystalline index change in cellulose during aerobic and anaerobic Cellulomonas uda growth

N2{\text{ }} \cdot {\text{ Y}}_{{\text{CH}}{}_{\text{4}}}

Microcalorimetry: A tool for the study of the biodegradability of straw by mixed bacterial cultures

and the maintenance coefficient varied with the gas input and with the nitrogen source. Growth of Methanococcus thermolithotrophicus in continuous culture in a fermenter gassed with H2, CO2 as nitrogen, carbon and energy sources was also examined.

Influence of pretreatments on the fermentation of barley straw by undefined mixed bacterial populations

SummaryA thermophilic methanogenic bacterium, Methanococcus thermolithotrophicus, was grown on H2 and CO2 in both batch and continuous culture, in a fermentor equipped with either a straight blade impeller or a Rushton impeller. Production was continued until 470 l CH4·l-1 per day was obtained with a biomass of 3.5 g dry wt. l-1 under batch conditions.

New Shuttle Vectors for the Introduction of Cloned DNA inDesulfovibrio

SummaryCultures of Cellulomonas uda were monitored under both aerobic and anaerobic conditions using three commercially available celluloses with varying degrees of crystallinity. In all cases, a high level of cellulose was metabolized and the same maximum carboxymethylcellulase activity (2.6 IU/mg of cellular protein) was observed. Measurement of the crystalline index of celluloses during cellulose growth revealed that the amorphous and crystalline regions were solubilized simultaneously. Investigation of the solubilization rate showed that a decline occurred when a considerable amount of cellulose still remained in the medium. Hypotheses were suggested to explain the biphasic pattern of the kinetics obtained.

Analysis ofthePeriplasmic (NiFe) Hydrogenase Transcription UnitfromDesulfovibrio fructosovoranst

SummaryA microcalorimetric study is proposed to follow the degradation of straw by a mixed bacterial culture. The effect of an alkali pretreatment of straw is described.

Process for the production of methane has high performance culture Methanobacterium thermoautotrophicum or any methanogenic bacteria having the same physiological growth properties

SummaryThe biodegradability of straw by a mixed bacterial culture obtained from a pile of weeds was studied by microcalorimetry. All the cultures were grown at 30°C under anaerobic conditions in microcalorimetric vessels. The fermentation thermograms, obtained using well defined conditions, were very reproducible. The quantities of heat produced during straw degradation were found to be proportional to the quantity of straw introduced at the beginning of the fermentation.The recovered carbon was also found to be proportional to the initial quantity of straw. From both microcalorimetric and chemical analysis it was concluded that the limiting factor of the straw degradation was the cellulolytic activity of the mixed culture. This is supported by the fact that commercially available cellulase added to the growth medium increases the amount of straw degradation by about four times. The heat associated with fermentation of each cellulose monomer (C6H10O5) was found to be 120 kJ, a value which is close to the heat associated with hexose fermentation by pure cultures. In conclusion, we propose that microcalorimetry can be used as a powerful tool for the analysis of the biodegradability of complex heterogeneous substrate by pure or mixed cultures.