Study On The Degradation Performance And Mechanism Of Formaldehyde Waste Gas Bvyfunctional Bacteria

Formaldehyde?HCHO?is a irritative gas with high toxicity and volatile,but also has large water-solubility.It is carcinogenic,teratogenic and ranked No.2 on the list of priority control of toxic chemicals.The main source of formaldehyde pollution come from coatings,plastics,organic synthesis,decoration materials and paint industry,where discharge waste water and gas.Some studies have reported that formaldehyde is also one of the most abundant indoor pollutants.Moreover,indoor walls,ceilings,furniture and adhesive,released formaldehyde into the surrounding environment with the aging of the materials gradually.Formaldehyde not only endangers the ecological environment,but also is threatening human health.So,when human use formaldehyde as industrial raw material,the waste gas pollution control and the mechanism of the related process are becoming hot topic in the field of air pollution prevention and control.In this study,the technology of purifying formaldehyde waste gas by biological method,which was economical and effective and suitable for the treatment of various kinds of industrial waste gas,was adopted.The aim was to screen the dominant bacterium with high biodegradation ability in biofilm-packing towers.Studying on the degradation of formaldehyde under different conditions,Respectively used the degrada-tion bacterium whose were isolated successfully.And activated sludge domesticated microbes to hang the membrane for biofilm packing tower,to know the formaldehyde emission degradation performance of two towers.By using GC-MS analysis and ELISA,the mechanism of the related process for the dominant bacteria was studied,which was to understand the processing mechanism of purifying formaldehyde by the dominant bacterium in the tower,and provide theoretical support for biodegradation and treatment of industrial formaldehyde pollution areas in the future.The main contents and conclus-ions were as follows:?1?Bacterium capable to degrade and metabolize formaldehyde as a sole carbon source and energy,were isolated from the ceramist covering with biofilm in packing towers.Were identified formaldehyde-degradation bacteria by the results of methods for environmental microbial analysis,physiological,biochemical tests,and 16S rDNA gene sequence analysis.Two Strains named P₁ and Q₁,which were isolated and identified as Pseudomonas sp.and Methylobacterium sp.?2?Studying on degradation effect of Pseudomonassp.P₁ and Methylobacterium sp.Q₁ in terms of purifying formaldehyde and its influencing factors.Under the condition of liquid culture,the experiments on the degradation of formaldehyde by strains showed that,under the same cultural condition,the 92.8%was degraded by Pseudomonas sp.P₁in 44 h.And the 97.9%in formaldehyde degraded by Methylobacterium sp.Q₁ in 28 h,when containing the concentration of formaldehyde was 300 mg/L in culture medium.While original concentration was below700 m/L,it could be degraded completely by Pseudomonas sp.P₁ and Methylobacterium sp.Q₁,and Methylobacterium sp.Q₁ was well tolerated in higher concentration formaldehyde comparing with strain P₁.The orth-ogonal design experiment showed that the influence factors of the three factors on the rate of formaldehyde degradation for Pseudomonas sp.P₁ and Methylobacterium sp.Q₁were as follows:formaldehyde concentration>pH>inoculums.The effect of formalde-hyde concentration in three factors was more significant.?3?Research on the purification performance of biofilm-packing towers for formal-dehyde waste gas.The tower 1,which was covered with activated sludge,and the tower2,in which the formaldehyde degrading bacteria attached to the membrane,were taken as the research objects.While the flow rate was 200 L/h,the inlet concentration of formaldehyde was 450 mg/m³,the efficiency of gas phase formaldehyde purification in the tower was above 99%.The maximum biochemical remove capacity of two towers respectively reached at 10.76 mg/?L·h?and 9.11 mg/?L·h?,and the accumulation of liquid formaldehyde in tower 3 as blank group also increased with the increasing of formaldehyde gas.Two towers in the concentration of 791.07 mg/m³ and 813.23 mg/m³had the biggest removal 11.54 mg/?L·h?and 14.63 mg/?L·h?.?4?The test for key enzyme activity and mechanism of the related process to the dominant bacterium which were Pseudomonas sp.P₁ and Methylobacterium sp.Q₁ was studied by using GC-MS and ELISA.Results showed in the process of biodegradable formaldehyde,they producing organic acids,amino acids,sugars,fatty acids and others.The enzymatic properties of the key enzyme,SHMT and PHI,were identified.It can be inferred that the main pathway of formaldehyde metabolism of these two bacteria were serine pathway and RuMP.