Psychrotrophs and application thereof in wastewater treatment

[0021] Example 1: Screening and Identification of Bacterial Strains

[0022] Of the three strains provided by the present invention, L126 is named Janthinobacterium lividum, L146 is named Flavobacterium hercynium, and L188 is named Pseudomonas gessardii. At present, the three strains have been deposited in the International Depository of Microorganisms of the Budapest Treaty: China Microorganism Culture Preservation Management Committee on General Microbiology Center (CGMCC). Address: Institute of Microbiology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, Zip code: 100101, date of deposit is March 18, 2009, and deposit numbers are CGMCC No 2956, CGMCC No 2957, and CGMCC No 2958.

[0023] Pyrotrophic bacteria L126, aerobic, Gram-negative, rod-shaped without spores, motile; the colony is white in the early stage, and turns purple in the later stage, with smooth, moist, round, and neat edges; growth temperature 4-35°C, 37°C No growth, the optimum growth temperature is 15°C, see attached figure 1; NaCl tolerance concentration is less than 4%, can not tolerate 0.5% SDS; catalase, oxidase, starch hydrolysis positive, esterase reaction negative; glucose, mannose, mannitol, malate, citrate , phenylacetate as the sole carbon source for growth. According to "Bergey's Bacteria Identification Handbook", the morphological, physiological and biochemical measurements of the L126 strain were carried out, and then the 16S rDNA sequence determination and homologous evolution comparative analysis were finally determined to be Janthinobacterium lividum.

[0024] Pyrotolerant bacteria L146, aerobic, Gram-negative, rod-shaped without spores; no obvious motility; colonies are yellow, round, smooth, moist, viscous and expanded; the growth temperature range is 12-29°C, the optimum growth The temperature is 20°C, below 7°C or above 30.5°C cannot grow, see attached figure 1;Grow when NaCl concentration is 1%, not grow when the concentration is 4%; cannot tolerate 0.5% SDS; catalase, oxidase, esterase reaction positive; starch hydrolysis positive, able to utilize glucose, dextrin, liver Sugar, D-arabinitol, D-cellobiose, D-fructose, D-galactose, D-trehalose, L-aspartic acid are the only carbon sources. According to the "Bergey's Bacteria Identification Manual", the morphological, physiological and biochemical measurements of the L146 strain were carried out, and then the 16S rDNA sequence determination and homologous evolution comparative analysis were carried out, and the strain L146 was finally determined to be Flavobacterium hercynium.

[0025] Pyrotrophic bacteria L188, aerobic, Gram-negative, rod-shaped without spores; motile; colonies are white with yellowish, slightly convex center, round or irregular, smooth and moist surface; growth temperature range 4-37 ℃, It does not grow above 40°C, and the optimum growth temperature is 20°C, see attached figure 1;Grow under the condition of 1-4% NaCl concentration, but do not grow when the concentration is above 5%; can tolerate 0.5% SDS; catalase, oxidase reaction is positive, esterase reaction is negative; starch hydrolysis is negative, can utilize glucose, arabic Sugar, xylitol, fructan, ribitol, and erythritol are the only carbon sources. According to "Bergey's Bacteria Identification Handbook", the morphological, physiological and biochemical measurements of the L188 strain were carried out, and then the 16S rDNA sequence determination and homologous evolution comparative analysis were finally determined to be Pseudomonas gessardii.

[0026] Strains L126, L146, and L188 can be preserved for a long time by subculture on inclined planes, vacuum freeze-drying, or embedding in liquid paraffin. Among them, the slant culture method is to carry out proliferation culture on a solid medium suitable for the strain, place them at the optimum culture temperature for 3 to 5 days, and store them at a constant temperature at 4°C after the colonies are formed. Passed down once a month. Use vacuum drying method or liquid paraffin embedding method to preserve the strain, and it can be preserved for more than 1 year at low temperature or normal temperature.

[0027] Embodiment two: the mensuration of growth curve of psychrotroph L126, L146, L188

[0028] Inoculate three strains of psychrotrophic bacteria L126, L146, and L188 in 5ml of complete liquid medium respectively, and culture them at 10°C and 180rpm for 24 hours, then inoculate 0.1ml of the bacterial suspension into 25ml of fresh complete liquid medium, under the same conditions Under culture, samples were taken at regular intervals to measure the absorbance value (OD) of the bacteria. 600 ), draw the growth curve, the results are shown in the attached figure 1 shown.

[0029] The results showed that the three strains could grow well under the low temperature condition of 10℃, but their growth rates were different; L188 had reached the maximum growth at 20 hours, while L146 grew slowly and had not reached the maximum growth at 42 hours. In mixed culture, different bacteria can play a role in different time periods.

[0030] Embodiment three: the influence of temperature on bacterial strain treatment effect

[0031] Inoculate three strains of psychrotrophic bacteria L126, L146, L188 and mesophilic strains Escherichia coli (E.coli) and Bacillus subtilis (S.subtilis) in complete liquid medium, place them at their respective optimum culture temperatures, and cultivate them at 180rpm After 20-24 hours, inoculate in simulated domestic sewage with 10% inoculum amount, incubate with 180rpm aeration, and measure the COD value change of simulated domestic sewage within 24 hours at 10°C, 15°C, 20°C, and 30°C respectively. The measurement results can be found in the appendix figure 2 shown.

[0032] The results showed that, compared with mesophilic bacteria Escherichia coli (E.coli) and Bacillus subtilis (S.subtilis), the degradation efficiency of psychrotrophic bacteria L126, L146 and L188 was significantly higher than that of mesophilic bacteria at low temperature; L126 and L146 , L188 strain has a good treatment effect in the range of 10-20 ℃, the treatment efficiency is remarkable at low temperature, and it has good resistance to temperature change.