Isolation And Identification Of A Strain Degrading Malachite Green,the Characteristics Of Degrading And The Research Of Degrading Mechanism

Triphenylmethane dye become the third most widely used dyes in the world after azo and anthracene ketone dyes.Widely used in paper industry,textile industry,pharmaceutical industry and aquaculture industry.Malachite green functional group trityl have high chemical stability,and low biodegradable,therefore,its have some toxic side effect include high toxicty,high residual,carcinogenic and mutagenic and so on.Emissions waste water with it to the environment make a great threat to the health of humans and other creatures.Biodegradation due to its advantages of economy,environment,simple operation and so on,is considered to be the most effective method for such waste water degradation.So far,has already separate various degradating bacteria such as bacteria,fungi,yeast and so on.But looking for more efficient,rapid degradation strains of malachite green,study the character of their growth and degradation still has the vital significance.This subject introduces a strain isolated from a dyeing sewage sludge that can efficiently degrade malachite green.studying their characterizes of physiological and biochemica,Growth and degradtion,enzymology,exploring degradation mechanism of Malachite green.For triphenylmethane wastewater treatment provides strain resources and theoretical basis.With the method of enrichment cultivation,isolated the strain which can better decoloration of malachite green from the sludge which contaminated with dye for many years,named KL-1.Strain KL-1 was identified preliminarily as Pseudomonas sp.according to its morphology and the character of physiological and biochemical.The paper explored the optimal growth conditions of the strain SJ-1,the optimal growth temperature and initial pH of the strain SJ-1 were 30?and 6.0;With the increased of liquid medium volume,the growth of the strain is on the decline;Strains can use less carbon source,in the selected carbon source,which can grow in the inorganic salt medium only with glucose,and grow better in the medium containing peptone and yeast powder;In the experiment of nitrogen source,all the inorganic nitrogen source have good role in promoting the growth,organic nitrogen source peptone and yeast powder can support the growth more apparent compare to inorganic nitrogen sources;In the medium of LB,the growth of the strain KL-1 in 0-2 h was the lag phase,the exponential phase was in 2-6 h,the stationary phase was in 6h later.The optimal degradation conditions with strain KL-1 research shows that,In LBmedium,The strain KL-1 could degrade 100mg/L malachite green in 6h.Our experimental results show that the temperature needed to remove strain KL-1from the malachite green is30?;and in pH7.0 14.0 scope can be degrade malachite green,and the decoloring rate can reach more than 72%;Fluid volume on KL-1 had a greater influence on the degradation of malachite green,decoloring rate decreased as the amount of liquid loading;The decoloring rate decreased with the increased of initial concentration of malachite green,when the concentration less than 200mg/L,malachite green decoloring rate above 80% in 4h.Degradation of spectrum experiments showed,the strain KL-1 have relatively wide spectrum of degradation,within 20 mg/L of azo dye methyl red,triphenylmethane dye crystal violet,Victoria blue degradation rate above 90% in 5d,the degradation rate of bromothymol blue,methyl orange,fuchsin,Sudan ? is above 56%.Studies have shown that enzymology characteristics:enzymatic reaction system was established,The results show that the malachite green Degradation enzyme in KL-1 located out the cell membrane,and belonged to constitutive enzyme;The option enzymatic reaction temperature was 30 ?;The optimum reaction pH was 7.0;Fe²⁺ and Mg²⁺ on the degradation enzyme of malachite green with a little boost,The relative enzyme activity increased by 5.26% and 5.26% respectively.Ag+?Hg²⁺?Fe3+?Ca²⁺?Zn²⁺?Mn²⁺?Cu²⁺ on degradation enzyme all have inhibited on it;Organic solvents all have different degree of inhibition on degradation enzyme.The enzyme was most stable in methanol and ethanol,The relative enzyme activity reduced about 10% only,methylene chloride,chloroform and acetone have bigger suppression on it,the relative enzyme activity were decreased by over 50%.Degradation pathway experiments show,The strain in the process of degrade malachite green,there may be two types of degradation products:leuco malachite green and phenol.Degradation pathway as follows:First step may be reductive metabolism become fat soluble recessive malachite green,after further degradation,and eventually generate phenol with oxidative cracking and demethylation.