抄録
About 400 aerobic heterotrophic bacteria, including three pollution and one unpollution index bacterial types, isolated from a total of 22 stream waters were examined to determine their utilization of low molecular weight organic compounds and their hydrolysis of high molecular weight organic compounds. The results showed that the ability to utilize low molecular weight organic compounds of two yellow pigmented bacterial types of the pollution index bacteria was much lower than that of other bacterial types. Those two bacteria which could not completely utilize the low molecular weight organic compounds, Flavobacterium YA1 and Flavobacterium YI, were then investigated. The quality of stream water was found to be reflected only by these two types, because the ratio of these isolates positively correlated significantly with many water quality variables. In investigating the validity of these bacteria as pollution indicators, the bacterial number of Flavobacterium YA1 in polluted water with domestic waste was much higher than that in clean water such as tap water, whereas Flavobacterium YI was detected only in clean water. These results suggest that Flavobacterium YA1 may be a good candidate as a pollution indicator of domestic waste in stream water.
