The studies of measurement of microorganisms and rapid degradation activity in methane fermentation reactor.

Research Project

Project/Area Number	06454107
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	生物環境
Research Institution	University of Tsukuba
Principal Investigator	MAEKAWA Takaaki University of Tsukuba, Institute of Agricultural and Forest Engineering, Professor, 農林工学系, 教授 (40015665)
Project Period (FY)	1994 – 1996
Project Status	Completed (Fiscal Year 1996)
Budget Amount *help	¥6,500,000 (Direct Cost: ¥6,500,000) Fiscal Year 1996: ¥1,600,000 (Direct Cost: ¥1,600,000) Fiscal Year 1995: ¥2,700,000 (Direct Cost: ¥2,700,000) Fiscal Year 1994: ¥2,200,000 (Direct Cost: ¥2,200,000)
Keywords	coenzymeF420 / methane production ratio / hydrogenotrophic methanogens / acetotrophic methanogens / image analysis / methane fermentation / CO_2資化性メタン菌 / 画像処理 / 酢酸分解系メタン菌 / 褪色 / F_<420>補酵素 / 2値化処理
Research Abstract	The fluorescence coenzyme F420 was measured as an indicator of methanogenic fermentation. Coenzyme F420 plays a key metabolic role in methanogenic bacteria as an electron carrier in both anabolic and catabolic redox reactions. It is found in all methanogenic bacteria, but not in other organisms involved in the digestion process. Coenzyme F420 is strongly autofluorescent and can be measured by fluorescence microscopy. An experimental system composed of fluorescence microscopy, CCD camera, and an image analyzer was constructed to measure coenzyme F420. The liquid portion from the methanogenic fermentor was irradiated at an excitation light of 420nm and observed by fluorescence microscopy. An fluorescence image of the methanogen was taken by a CCD camera. The rate of fluorescence pixels per picture (%) was calculated by an image analyzer. It indicates the coenzyme F420 concentration in methanogenic fermentor. Changes of the fluorescence pixels rate was measured during batch growth of acefotrophic and hydrogenotrophic methanogens. Correlation between the fluorescence pixels rate and the methane production ratio (ml/hour) in both methanogens was high. Because a methane productivity is closely related to the coenzyme F420 concentration in the reactor. However, correlation between the MLVSS (mg/L) and methane production ratio was not high. The coefficient of correlation in hydrogenotrophic methanogen (r=0.93) was higher than that in acetotrophic methanogen (r=0.81). This measurement can potentially help to characterize more metabolic status of the methanogenic bacteria. The experimental system is available for on line, real time measurement.