Heterotrophic nitrification engineering bacteria capable of achieving nitrite nitrogen accumulation and building method thereof

Abstract

The invention provides a building method of heterotrophic nitrification engineering bacteria capable of achieving nitrite nitrogen accumulation. The building method comprises the steps that 1, heterotrophic nitrification bacteria with NO2--N as the main nitration product are selected as test bacteria; 2, whole genome sequence sequencing analysis is carried out on the test bacteria, the positions of sequences of nitrite reductase genes to be deleted and all homologous genes in gene sequences are recognized and determined; 3, the PCR technology is utilized for amplifying recognized nitrite reductase gene sequences to obtain a homologous arm sequence, the homologous arm sequence is linked to a carrier with marker genes to form donor strains, the donor strains and test bacteria are subjected to inoculated culture, and finally a specific site expression method of marker genes is adopted for obtaining bacterial strains with nitrite reductase genes successfully deleted; 4, operations in the step 3 are repeated till all the homologous genes are successfully deleted, and finally the heterotrophic nitrification engineering bacteria capable of achieving NO2--N accumulation are obtained.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment, in particular to a method capable of realizing nitrite nitrogen (NO 2 - -N) enriched heterotrophic nitrification engineering bacteria and construction method thereof, suitable for providing electron acceptor nitrite nitrogen (NO) for short-range denitrification process or anaerobic ammonium oxidation process 2 - -N). Background technique [0002] Nitrosification, short-range nitrification, is a new denitrification process developed by Delft University in the Netherlands. Its principle is to control the nitrification process at the nitrite stage and terminate it, and then directly carry out denitrification denitrification or anaerobicammonium oxidation technology (anaerobicammonium oxidation) , Anammox) provides NO 2 - -N as electron acceptor for oxidation of NH 4 + -N for denitrification. Compared with the full nitrification-denitrification reaction pathway, the short-cut nitrifi...

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Problems solved by technology

[0003] At present, the short-cut nitrification process adopts the method of enriching ammonia oxidizing bacteria (AOB) and inhibiting the growth of nitrous nitrogen oxidizing bacteria (NOB) to realize the accumulation of NO2--N. The main problems are as follows: (1) Using short-term sludge at high temperature The method of selective enrichment of AOB by age (SRT) and flushing out of NOB is only applicable to the case of low sewage treatment, because high temperature requires a lot of energy consumption

(2) The inhibition of NOB activity by low dissolved oxygen (DO) will lead to low nitrogen removal rate. In addition, the system is in a low dissolved oxygen state for a long time, and the activated sludge is easy to disintegrate and expand filamentously.

(3) Although the method of inhibiting NOB by using free ammonia (FA) can obtain the initial NO 2 - -N accumulates, but the effect cannot be maintained for a long time since NOB may gradually adapt to high FA concentration

In addition, FA can also inhibit Anammox bacteria, resulting in a decrease in the removal rate of the system

In addition, wastewater contains more or less a certain concentration of organic matter, which makes the growth of autotrophic AOB affected by heterotrophic bacteria