Polyculture enrichment screening method for ocean heterotrophic denitrifying bacteria

Abstract

The invention discloses a polyculture enrichment screening method for ocean heterotrophic denitrifying bacteria. With the method, the ocean heterotrophic denitrifying bacteria can be enriched in an early-stage autotrophic mode and a later-stage heterotrophic mode, and the bacteria with heterotrophic nitrification capability and heterotrophic nitrification and aerobic denitrification capability can be guaranteed to propagate. The polyculture enrichment screening method comprises the following steps: firstly, separating a selective culture medium; then, detecting and separating the ammonia monooxygenase gene and the nitrite oxidoreductase gene of a bacterial strain; finally, in a heterotrophic culture medium, determining whether a bacterial strain with a target gene is expressed or not by a nitrogen balance test. The autotrophic mode and the heterotrophic mode are alternately used for domestication and, enrichment as well as separation to finally obtain the screened bacterial strain which is determined as the heterotrophic nitrification bacterial strain or the heterotrophic nitrification and aerobic denitrification bacterial strain. The polyculture enrichment of heterotrophic nitrification and aerobic denitrification bacteria is not only the breakthrough of the bacteria enrichment theory, the bacterial strain is immobilized with a biofortification method to have a great practical application meaning for the biological denitrification of ocean cycling breeding wastewater, and the method is suitable for treating wastewater in the nitrification unit for the factory high-density breeding.

Description

Technical field: [0001] The invention belongs to the technical field of marine aquaculture wastewater treatment, in particular to a method for biological denitrification of industrialized high-density aquaculture wastewater. Background technique: [0002] Marine aquaculture is an important means to alleviate the pressure on human demand for food and avoid overfishing of marine biological resources. China's aquaculture industry has entered a stage of sustained and rapid development. The highly intensive farming methods have gradually revealed and become more prominent the pollution problems of the aquaculture industry, resulting in the deterioration of the aquaculture environment and the prevalence of diseases. The blind use of antibiotics in order to control diseases has caused serious damage to the entire aquaculture industry. huge economic losses. High-density factory farming in circulating water takes up less resources, and can produce commercial aquatic products through...

AI Technical Summary

Problems solved by technology

Biological denitrification is mainly accomplished in three ways. One is to use the photosynthesis of green plants to assimilate nitrogen-containing compounds in aquaculture wastewater to realize the circulation and treatment of aquaculture water. The biggest disadvantage is low efficiency and large footprint

The second is to use autotrophic nitrifying bacteria and anaerobic denitrifying bacteria to convert ammonia nitrogen into nitrite nitrogen, nitrate nitrogen, and finally into nitrogen to complete the whole process of biological denitrification. This method is the current high-density industrial aquaculture wastewater The main method of treatment, the disadvantage is that the autotrophic bacteria that complete nitrification are chemoautotrophic bacteria, the specific growth rate is low, the culture water is acidified, and the accumulation of nitrate nitrogen is often caused in the treatment system without denitrification unit , have adverse effects on the cultured organisms and the environment. At the same time, denitrification requires an anaerobic environment. The aquaculture water body is an oxygen-rich environment, which is difficult in actual operation.

The third method of biological denitrification is heterotrophic nitrification, which directly uses the assimilation of bacteria to transform and absorb nitrogenous substances in water bodies. The process is simple and the conversion efficiency is high. The biomass is large

CN03118598.3 describes the method for isolating heterotrophic nitrifying bacteria in soil, and Chinese patent applications 200510030456.3 and 200610010263.6 also describe the screening method for heterotrophic nitrifying bacteria. The disadvantage of the three methods is that they are directly separated and screened from the natural environment. There are many types of microorganisms, and the workload is relatively large