CO₂의 분압이 0.5기압일 경우 control 반응조와 비교해 메탄생성속도의 증가는 탄수화물을 기질로 사용한 반응조에서 20%, 단백질을 사용한 반응조에서 29%, 혼합기질 반응조에서는 26%로 단백질인 경우가 가장 큰 증가를 나타내었다. 가수분해 세균수, 황산염 환원세균수 및 수소생성 acetogenic세균수는 CO₂ 분압에 대해 거의 영향이 없었으며, 수소이용 메탄생성 세균수 및 Homoacetogenic 세균수는 CO₂의 분압이 0.1-0.6기압에서 CO₂ 분압의 증가에 따라 세균수는 증가를 나타내었다. 초산이용 메탄생성 세균수는 CO₂의 분압이 0.7기압 이상에서 CO₂ 분압의 저해로 인해 상당히 감소되었고, 초산분해 활성도 및 메탄생성 활성도는 CO₂의 분압이 0.5기압에서 가장 높은 것으로 나타났다. 또한, 메탄생성속도, 활성도 및 세균군에 대한 CO₂의 저해는 용액내의 유리 CO₂농도에 의존하는 것으로 판단된다.

Effects of carbon dioxide partial pressuree(PCO₂) and substrate compositions on the bacterial population, methane production rate and matter degradation in anaerobic digestion were investigated by using anaerobic chemostat type reactors at 35±1℃, at the HRT of 7 days. Two kinds of single substrate containing carbohydrate and protein, and mixed of these were used in this study. At PCO₂ of 0.5 atm, the specific methane production rate and specific substrate removal rate reached the maximum rates at the protein substrate reactor. At PCO₂ of 0.5 atm, the methane production rates in the reactors fed by carbohydrate, protein and mixed substrate were 20%, 29% and 26% higher than those obtained under the controlled condition, respectively. The number of acetate consuming methanogenic bacteria enumerated by the MPN(most probable number) method, decreased when PCO₂ exceeded 0.7 atm. Hydrogen consuming methanogenic bacteria and homoacetogenic bacteria increased as PCO₂ increased from 0.1 to 0.6 atm, however, decreased slightly at PCO₂ above 0.7 atm. The number of hydrolytic bacteria, sulfate-reducing bacteria and H₂-producing acetogenic bacteria were not much influenced by the change of PCO₂. The potential methanogenic activity reached the maximum at PCO₂ 0.5 atm, however, decreased significantly when PCO₂ exceeded 0.7 atm. It was considered that the inhibition of specific methane production rate at PCO₂ above 0.7 atm would depend on free CO₂ concentration in solution.

PCO₂ Methane Production Matter Degradation Bacterial Number Activity

Kazuki S, Shuichi O, The 7th International Symposium on Anaerobic Digestion (1994)
APHA, AWWA & WEF.: "Standard Methods for the Examination of Water and Wastewater," 15th ed., N.Y. (1987)
Herbert D, Phipps PJ, Strange RE, "Chemical Analysis of Microbial Cells," Academic Press London and New York, 210 (1971)
Miller TL, Wolin MA, Appl. Microbiol., 27, 985 (1974)
Braun M, Schoberth S, Gottshalk G, Arch. Microbiol., 120, 201 (1979) 
Chartrain M, Zeikus JG, J. Appl. Environ. Microbiol., 51, 188 (1986)
Zhang TC, Noike T, Water Res., 28, 27 (1994) 
Mitz MA, Enzyme Eng., 3, 235 (1978)
Tan KH, Gill CO, Meat Sci., 7, 9 (1982) 
Foster JW, Davis JB, Arch. Biochem., 21, 135 (1949)
Pirt SJ, J. Fermen. Technol., 65, 173 (1987) 
Wise DL, Cooney CL, Augensteein DC, Biotechnol. Bioeng., 20, 1153 (1978) 
Neil MD, Douglas BK, J. Appl. Bacteriol., 67, 109 (1989)
Wolfe SK, Food Technol., 34, 55 (1980)