... PC2 was considered to be mainly MK-8, because MK-9 and MK-10 contents were relatively small. From the results of PCA, Q-8, Q-9, MK-7 and MK-8 appear to be very important factors in DNR in the ... (Hiraishi et al., 1996). The molar ratio of menaquinone to ubiquinone (MK/Q) is used as an indicator of the respiratory state such as the balance between anaerobic and aerobic respiration. ... hamada34@affrc.go.jp Received July 31, 2010, Accepted October 21, 2010. - 421 - Evaluation of the Characteristics of Microorganisms that Contribute to Denitrification in the Paddy Drainage Treatment...