Screening Of Probiotics And Their Impact On Water Quality

In the aquatic water, the bait, fish waste and some other enrich nutritional factors cannot discharge in time and cause water pollution. Using of antibiotics and chemicals in frequent on the breeding will not only make harmful to microbial resistance, destroy the normal biological breeding environment system, and cause secondary pollution. Therefore, using biological methods to purify aquaculture water is best way to protect the water pollution.This study sampled from the aquaculture water, enrichment and purification of the bacteria. The primary screen was carried out by antibacterial effect, by getting down the aquaculture water chemical oxygen demand, ammonia nitrogen and nitrite nitrogen content to compound screen. The strains which have good effect to preliminary identify the morphological structure, physiological and biochemical. Finally the ingredients of medium and culture conditions were optimized.The 10 strains were obtained by primary screening which show inhibition to indicator bacteria, and three kinds of them obtained by the compound screen show good effect. The bacteria by preliminary identification is red swamp pseudomonas, bacillus licheniformis, bacillus subtilis. Through single factor and orthogonal test to determine the red swamp pseudomonas the optimal culture medium group is divided into: Brown sugar 5g/L, peptone 5g/L, magnesium sulfate 0.5g/L, sodium dihydrogen phosphate 0.5g/L; Culture conditions as follows: the initial pH 7, 3% inoculated quantity, with fluid amount to 5mL /100 m L bottle of triangle, culture temperature of 37℃. The optimal medium of bacillus licheniformis group is divided into: Brown sugar5g/L, peptone20g/L, magnesium sulfate1g/L, sodium dihydrogen phosphate 0.5g/L; Culture conditions as follows: the initial pH7.5, inoculation amount to 2%, with fluid amount to 20 m L/100 m L bottle of triangle, culture temperature of 40℃. The optimal medium of bacillus subtilis group is divided into: brown sugar 20g/L, peptone,5g/L magnesium sulfate0.5g/L, sodium dihydrogen phosphate 0.5g/L; Culture conditions as follows: the initial pH6.5, inoculation amount to 3%, with fluid amount to 5m L/100 mL bottle of triangle, culture temperature of 37℃.