The conditions of Pseudomonas sp.GX 4\|1 producing flocculant only using fish meal wastewater were mainly studied.Under the optimum culture conditions:medium COD 10g/L,initial pH 7～9,cultural temperature 30,and the shaking speed,100～250r/min,the flocculating rates can highly reach more than 97% with maxmium 99 5%,even if the culture medium was not sterilized.This flocculant shows high flocculating efficiency to kaolin clay suspension,soil suspension,activate carbon powder suspension and wastewater fromelectroceramics plant.

Pseudomonas XN 1 has the ability of degradation for organic pollutant nitrobenzene, and the resistance to ampicillin In this paper, the plasmid was detected and isolated from the cell of Pseudomonas XN 1, and plasmid pXN 1 whose size is about 22 kb was gained The experiment of plasmid elimination confirmed that the plasmid has some relation to the ability of nitrobenzene degradation, while it is irrelevant to the resistance to ampicillin The feature difference between XN 1and its spontaneous mutants was corresponding to the difference of the plasmids detection, and a derivative plasmid pXN 13 was obtained from mutant XN 13 which is a few kb smaller than pXN 1