High Salinity Wastewater Treatment Identification And Growth Characteristics Of The Advantages Of Salt-tolerant Bacteria In A Preliminary Study

The topic takes salt-tolerant microorganism as the research object,four strains of bacterium identified as superiority halotolerant were isolated from salt-resistant activated-sludge,which was cultivated by A/O process in aquatic product processing wastewater simulated.And studied on salt tolerance,morphological observation, physiological and biochemical characteristics,16s rDNA sequence homology analysis,and also built phylogeny tree to them.Studied the effects of different environmental factors (temperature,pH,sea water ratio) to the four stains'growth characteristics,especially the effect of salinity.In addition,a salt-resistant strain with abviously denitrifying characteristics was sceened from the four strains.And not only studied the effects of different environmental factors(carbon source,C:N mole ratio,pH,sea water ratio)to its denitrifying characteristics,but also studied its denitrification capacity when took NO₂^-N as the only nitrogen source under the optimum condition.The result of this paper can provide a scientific basis and microbiological basis for high salt wastewater biological treatment.The research to the four salt-resistant strains shows that:one shtain(symbol number is nyj1) belongs to chain bacillus,no significant rod-globosity variation period,can grow even when NaCl's concentration is 5%,has nothing special characteristics;one shtain (symbol number is nyj2) has significant rod-globosity variation period,main existing forms of short bacillus,spherical,can grow even when NaCl's concentration is 10%,and has abviously denitrification characteristics;one shtain(symbol number is nyj3) is short rod bacteria,main existing forms of single,double,or chain rods,can grow even when NaCl's concentration is 15%,possesses slight nitrosation ability;one shtain(symbol number is nyj4) is single,double rods bacteria,can grow even when NaCl's concentration is 5%,possesses denitrifieation ability.According to morphological observation,physiological and biochemical characteristics and 16s rDNA sequence homology analysis,it was showed that nyj1 should be Bacillus,and were with 99%,99%,99%,99%,100%,99%,99%,99%,99%sequence similarity to Bacillus cereus strain D62,Bacillus sp.cp-h63,Bacillus sp.cp-h45,Bacillus sp.B232 Ydz-hn,Bacillus sp.B75 Ydz-zz,Bacillus sp.Z7,Bacillus sp.Cobs2Tis11, Bacillus cereus strain 42112,Bacillus sp.cp-h36,which were in the same branch;nyj2 should be Arthrobacter,and were in the same branch with 98%sequence similarity to Arthrobacter protophormiae;nyj3 should be Bacillus,and were in the same branch with 99%sequence similarity to Bacillus sp.VAN14;nyj4 should be Alcaligenes,and were in the same branch with 99%sequence similarity to Alcaligenes sp.LJ-F.The research to the four stains' growth characteristics showed that:the optimum temperature is 30℃and the optimum pH is 7.5.In this experimental condition,nyj1,nyj2, nyj3 entered logarithms growth period after one hour' lag,nyj4 entered logarithms growth period after three hour' lag,when inoculated into 30%,50%,70%sea water ratio medium; the growth rate of four bacterium is quiker and generation time is shorter when were under the 30%sea water ratio medium than under the 50%,70%sea water ratio medium, the growth rate of four bacterium is the lowest and generation time is longest when were under 70%sea water ratio medium.The effects of saility is slightly to nyj1,but abviously to the others,especially to nyj2.The research on the salt-resistant nyj2 with the abviously denitrification characteristics shows that:the denitrifying process of nyj2 is that,firstly reduce nitrate into nitrites,and transforme them into nitrogen at last.The most optimum carbon source is sodium citrate,the most optimum C:N(mole ratio) is 8.0:1.0,the most optimum temperature is 30℃,the most optimum pH is 8,and under this experimental condition, strain nyj2 possesses stronger denitrifying ability when the sea water ratio is 30%,the second place is 50%,and the last is 70%,abviously,strain nyj2 is greatly influenced by salinity;under the same experimental condition,took NO₂^--N as the only nitrogen source, the NO₂^--N average removal efficiency was above 30%.