Isolation, Identification Of A Octylphenol Polyethoxylate High-effective Degradaing Strain And Its Degradation Characteristics

As a kind of non-ionic surfactant with excellent properties, OPnEO (Octylphenol polyoxyethylenes) are widely used in washing, textile, leather, paper making, pesticide and other fields. OPnEO and its intermediate metabolites, which are characterized by refractory, hydrophobic, fat-soluble and bioaccumulation, if used extensively, are bound to cause environmental pollution problems. The methods of OPnEO pollution governance include physical method, chemical method, physical chemistry method and biodegradation method, among which biological degradation has attracted widely attention because of its good biodegradable effect, low cost and no secondary pollution etc. Thus, on the basis of having obtained a degradation bacteria H1, which can degradation of high concentrations of OPnEO, this paper make a further appraisal of degrading bacteria on the system development. Besides, characters of antibiotic-resistant, ability against chromium toxicity, degradation of substrate for broad-spectrum and characteristics are studied. In addition, OPnEO degradation products of degradation bacterium H1were tested and analyzed by liquid chromatography-mass spectrometry (LC-MS). And the degradation mechanism and ways are preliminary studied and speculated. The main conclusions are as follows:(1) Screening and identification of degrading bacteria H1. The inorganic salt medium, of which TX-100are the sole carbon source, are adopted to screen. The degrading bacteria, named H1, capable of withstanding high concentrations TX-100and possessed good degradation performance, was obtained by enriching, separating and purifying. We use the method of gradually increasing TX-100concentration to domesticate degrading bacteria H1, which make H1grow normally in inorganic salt medium containing3g/L TX-100. Base on morphological observation, physiological and biochemical identification and16SrDNA(GenBank Accession No. KC505179) similarity analysis, the bacteria HI was identified as Acinetobacter calcoaceticus, a new species of TX-100degradation. Drug susceptibility results showed that the bacteria H1resistant to multiple antibiotics. Further, it is also found that the Strain H1has a certain tolerance of chrome.(2) The research of OPnEO degradation way. The study of the strain growth curve using different media and detection of degradation products of TX-100showed that the C2H2O3and OP4EC were generated in degradation process. Initially speculated that the degradation of OPnEO model is terminal oxidation, starting first from the oxidation of the terminal EO, followed by scission of the neighboring ether bond to form the EO chains shortened by one EO unit, with liberation of glyoxalic acid.(3) Study the degradation substrates of broad spectrum on the strain H1. Study of Acinetobacter calcoaceticus H1showed it could grow in high concentrations SDS environment. Investigation of its degradation characteristics showed that its optimum temperature of SDS degradation was30℃, the optimum pH was7, the optimum inoculation amount was2%and this strain is able to adapt to low osmotic pressure environment. When the concentration of SDS was less than400mg/L, the degradation rate of strain H1to SDS was above85%. Moreover, when the concentration of SDS was400mg/L, the maximum degradation rate of SDS reaches94%. When the concentration of K2Cr2O7was500mg/L, the degradation rate of strain H1to SDS was around50%. Adding the yeast extract can promote the degradation of SDS. Adding a certain amount of TX-100had little effect on the growth of strain H1and degradation of SDS, but great effects on the degradation of TX-100.(4) Analysis of the degradation causes of strain H1. The plasmid detection result showed that strain H1contains a plurality of plasmid DNA bands and may be more than one plasmid.Through the research of prime strain and derivative strains by the plasmid elimination, we found that not only the degradation of the surfactant TX-100and SDS degradation plasmid, but also ampicillin, amikacin and cotrimoxazole resistance are associated with plasmid.