Study On The Improvement Potential Of Saline-alkali Tolerant Multi-functional Paenibacillus Bacillus To Soda Saline-alkali Soil

With the continuous expansion of the area of saline-alkali soil,the saline-alkali soil has no grass,which seriously restricts the development of local agriculture and animal husbandry.Therefore,the improvement of saline-alkali soil is imminent.At present,the main problems in the existing research are that the use of microorganisms to improve the soda saline-alkaline soil is relatively small,the bacterial resources are scarce,and the available microbial resources are few.Most of the microbial functions obtained by the research are single and cannot be fully adapted and improved Soda saline soil,the soil improvement effect is not ideal.Therefore,this article uses the multifunctional saline-tolerant indigenous microorganisms isolated from soda saline-alkaline soil to improve the soda-alkaline soil in western Jilin Province.The main research results are as follows:(1)In this paper,a multifunctional bacterium that is salt-tolerant,can use glucose to produce acid to dissolve calcium phosphate,release phosphate ions,can degrade straw to produce cellulase,and release extracellular polysaccharides,was isolated and obtained by Gram staining.,Physiological and biochemical reactions and phylogenetic analysis showed that the strain was Paenibacillus sp.and named it C1.Strain C1 can grow rapidly in LB liquid medium,with an OD600of 0.875 at 24 h.When Na Cl is added at 7%and p H is 11,it still maintains good growth ability and has strong tolerance to saline and alkali.(2)Strain C1 can produce acid in the modified NBRIP medium,reducing the p H of the fermentation broth to 4.60,the phosphate concentration of the fermentation broth is 141.70 mg/m L,the acid-producing species is malic acid,and the content is 104.92?g/m L.Under different environmental conditions,changing the nitrogen source,carbon source,phosphorus source,Tris-HCl buffer,and Ca²⁺concentration all have different effects on the phosphate concentration of the fermentation broth of strain C1.Experimental studies show that the optimal medium conditions for strain C1 are:ammonium sulfate as the nitrogen source,glucose as the carbon source,and calcium phosphate as the phosphorus source,the strain C1 has the best phosphorus solubilization effect.(3)Strain C1 can produce cellulase in the straw degradation medium,and different salinity has an effect on the enzyme production capacity of strain C1 and the content of extracellular polysaccharide.When there were corn and rice straw in the medium,the cellulase activity decreased with the increase of Na Cl addition;it increased with the increase of the initial p H of the medium,and the yield of extracellular polysaccharide degrading rice straw was higher than that of corn straw.With the increase of time,when the amount of Na Cl added was 1%,the cellulase activity of rice and corn stover reached the maximum on the 4th and 5th d,respectively,and the highest were1122.72 U/m L and 336.29 U/m L,respectively;When the initial p H of the medium was 11,the cellulase activities of degrading rice and corn straw were 1459.67 U/m L and 491.02 U/m L,respectively.It can be seen that the degradation effect of strain C1 on rice straw is better than that of corn straw.The research on the degradation characteristics of rice and corn stalk by strain C1showed that the removal rate of rice stalk degraded by strain C1 was higher than that of corn stalk,and the removal rate was 52.24%on the 10th day.By scanning electron microscopy(SEM)analysis,strain C1 secreted cellulase activity to degrade the original flat,compact,smooth and regular structure of rice straw into regular block-like structures,changing from compact to loose,and the surface of the straw The structure was disrupted and destroyed.(4)The compound improvement effect of adding strain C1 with rice straw,ammonium sulfate and calcium phosphate to soda saline soil is better than adding only strain C1.The former can reduce the soil p H from 8.47 to 8.13 and the conductivity to 0.225m S/cm,The polysaccharide content,available phosphorus content,organic phosphorus content,alkaline phosphatase activity and total organic carbon content increased by 36.10%,40.48%,54.73%,23.93%and 31.26%,respectively,which increased and decreased the UV absorption value.The content of ionic carbon reaches a significant level,and at the same time promotes the formation of large aggregates,and significantly increases the stability of the aggregates in water.The polysaccharide content and total organic carbon content of different particle size aggregates are also significantly increased,>0.25mm The polysaccharide content of 0.25-0.053 mm and<0.053 mm granular aggregates increased by 35.86%,38.46%,and 31.23%,respectively,and the total carbon content increased by 35.69%,36.78%,and 25.44%;the available phosphorus content increased by 36.44%,29.49%and 38.72%;organic phosphorus content increased by 44.97%,41.37%and 39.26%,respectively;alkaline phosphatase activity increased by 26.11%,22.59%and 25.71%,reaching a significant level.The above research results show that a Bacillus-like bacillus isolated from the soda saline-alkaline soil,which is resistant to saline and alkali and has the ability to produce acid-soluble phosphorus,straw degradation and exopolysaccharide production,has important application value in the improvement of the soda saline-alkaline soil.Bacteria together with rice straw,ammonium sulfate and calcium phosphate can improve the aggregate structure of soda saline-alkali soil and increase the content of available nutrients,which can be used for the improvement of soda-alkaline soil.