固定化微生物对养殖水体中NH_4~ -N和NO_2~--N的转化作用

采用聚乙烯醇 (PVA) (ρ=gL-1)的方法对沼泽红假单胞菌、诺卡氏菌和假丝酵母 3种菌株进行固定化 ,所得的凝胶颗粒机械强度好 ,经久耐用 .运用这 3种菌株的固定化细胞对养殖水体中NH 4 N和NO-2 N进行转化 ,其最适作用温度范围为 2 5～ 30℃ ,最适pH范围分别为 :6 .5～ 8.5 ,7.0～ 7.5及 5 .5～ 7.0 ,且对水质初始氮浓度有很强的适应性 .3菌株经固定化后 ,其对养殖水体中NH 4 N和NO-2 N的转化效率明显优于其游离细胞 .若将 3菌株按 2 :1:2组合成复合菌株并固定化 ,其对养殖水体中的NH 4 N和NO-2 N转化效果将更佳 .图 3表 3参 9

TRANSFORMATION OF NH_4~ -N AND NO_2~--N BY IMMOBILIZED MICROORGANISMS IN AQUACULTURE WATER

Three strains of Rhodopseudomonas palustris,Nocardia and Candida sp. were immobilized with ρ(PVA)=100 g L-1. The gel beads were durable and had great mechanical strength. The three immobilized cells were used in transformation of NH+4-N and NO-2-N in the aquaculture water. The transformation was effective by the three strains with pH 6.5～8.5, 7.0～7.5, 5.5～7.0 and temperature 25～30℃.The immobilized cells were suitable for the initial concentration of NH+4-N and NO-2-N in the aquaculture water. Being immobilized, the three strains were able to transform NH+4-N and NO-2-N in to N2 and NO-2-N in the aquaculture water at a faster rate than that of their free cells. If the ratio of the immobilized compound strains of R.palustris to Nocardia to Candida sp. was 2:1:2, the transformation efficiency in the fishery water would be much better. Fig 3, Tab 3, Ref 9