汚濁海域におけるヘミセルロース分解細菌の生態に関する研究 Ｉ 広湾における海水中のヘミセルロース分解細菌の分布と環境因子

Abstract

On the coast of Hiro Bay in Seto Inland Sea, there is a kraft pulp mill whose effluent flows into the bay. Many workers have reported about organic pollutants and their influence on fishery in this area. Although microbiological work is indispensable for clarifying the mechanism of the decomposition of organic pollutants, little has been known about it. Therefore, a series of studies has been undertaken to clarify the microbial decomposition of hemicellulose in coastal waters polluted with pulp mill effluent. The distribution of heterotrophic bacteria and hemicellulose-decomposing bacteria, and the environmental conditions of seawater in the above-mentioned area were investigated five times from 1979 to 1981. The results obtained can be summarized as follows: The population densities of heterotrophic bacteria, glucomannan-decomposing bacteria, xylandecomposing bacteria and agar-decomposing bacteria per ml of seawater, were 102 to 107, 101 to 105, 101 to 106 and 101 to 105, respectively. The significance test of common coefficient regression analysis in the 1m layer of seawater showed that the population density of bacteria and the value of COD decreased with the distance from pulp mill. The ratio of the population density of xylan-decomposing bacteria to the population density of heterotrophic bacteria in the 1m layer of seawater was 10 to 1, 000 times as high as that in the control area (Yoshimi Bay), and similar to that in other pulp mill polluted ares (Iwakuni waters). Therefore, it can be said that this ratio may be one of the suitable indices for the pollution from plup mill.