Shaanxi Province Microbiology Institute

Fengcheng, China

Shaanxi Province Microbiology Institute

Fengcheng, China
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Zhen L.,Northwest Agriculture and Forestry University | Zhen L.,Shaanxi Province Microbiology Institute | Gu J.,Northwest Agriculture and Forestry University | Hu T.,Shaanxi Province Microbiology Institute | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

In order to investigate the mechanism of bioremediation of petroleum hydrocarbon-contaminated soil by composting, an experiment was conducted with bacteria agent and mature chicken manure as amendment. We studied the kinetics of petroleum hydrocarbon degradation and the diversity of microbial community during the bioremediation of petroleum hydrocarbon-contaminated soil by composting with different concentrations. The concentrations included 5000 mg/kg (T1), 10000 mg/kg (T2) and 50000 mg/kg (T3). The results showed that biodegradation of petroleum hydrocarbon followed the first-order model during composting. The constants of biodegradation rate in 3 treatments respectively were 0.012, 0.094 and 0.050/d. The half-life period was 6.79 d in T1 treatment, 7.37 d in T2 treatment and 13.86 d in T3 treatment. The average degradation rate was 112.08 mg/(kg·d) in T1 treatment, 230.05 mg/(kg·d) in T2 treatment and 887.93 mg/(kg·d) in T3 treatment during composting. This indicated that the average degradation rate increased with the increase in the petroleum hydrocarbon concentration. The average well-color development (AWCD) and use of carbon sources (except aromatic compounds) increased during the composting process, and reached the peak at the end of composting. There was a sharp rise in AWCD at the beginning of composting. This phenomenon could be easily explained by the fact that the total activity of soil microbial community increased significantly in the early of the process, while the use of carbon sources rose. The value of AWCD and the use of carbon sources in T3 were significantly higher than that in T2 and T3 at the end of composting. This demonstrated that there were dominant microbial consortia in the treatment with higher petroleum hydrocarbon concentration, and the dominant microbial consortia raised the total activity of soil microbial community and the use of carbon source. The dominant microbial consortia were metabolism communities of polymers and carbohydrates in composting process. The principal component analysis results revealed that there was a significant difference in soil microbial community structure among 3 treatments and the difference was mostly related to the use of carbohydrates and carboxylic acids. The microbial community diversity, as indicated by Shannon and McIntosh, increased during the composting process, and reached the peak at the end of stage. The values of Shannon and McIntosh in T3 were 0.21% and 17.64% higher than those in T1 respectively, and the differences were significant at 0.05 level (P<0.05). Simpson reached the maximum in middle stage. The value of Simpson in T1 was 2.12% and 9.44% higher than that in T2 and T3 respectively (P>0.05). This phenomenon was likely due to the stimulating effect of lower concentration of petroleum hydrocarbon on the growth of the dominant microbial consortia. However, the structure of soil microbial community in 3 treatments had no significant difference. The seed germination index (SGI) reached the maximum at the end of composting. Compared with the first stage of composting, the SGI in 3 treatments increased respectively by 18.26%, 20.42% and 36.41%. This suggested that bioremediation of petroleum hydrocarbon-contaminated soil by composting had a high effect for improving soil health. The results can provide a reference and theoretical basis for the application of bioremediation in petroleum hydrocarbon-contaminated soil in the Loess Plateau by composting with different concentrations. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.


Zhen L.,Northwest Agriculture and Forestry University | Zhen L.,Shaanxi Province Microbiology Institute | Gu J.,Northwest Agriculture and Forestry University | Hu T.,Northwest Agriculture and Forestry University | And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

To investigate the impacts of crude oil pollution on the soil microbial community, and estimate the potential for crude oil degradation by indigenous microbial consortia, we examined the soil microbial community structure, metabolic characteristics and functional diversity of crude oil-contaminated soil collected in the Loess Plateau in northern Shaanxi, using plate counts and the Biolog Eco plate method. The results showed that the responses of soil microbes to crude oil pollution stress varied greatly. The abundance of bacteria and fungi in crude oil-contaminated soil were about one order of magnitude higher than in the uncontaminated soil, while the abundance of actinomycetes was significantly lower in polluted soil than in uncontaminated soil (P<0.01). The number of bacteria in crude oil-contaminated soil was 107 CFU/ g, and the proportion of bacteria reached 99.8%—99.9% of all microbes. This indicated that majority of the crude oil biodegradation was the result of bacterial activity in collaboration with fungi rather than actinomycetes. The microbial activity of uncontaminated soil was higher than that of crude oil-contaminated soil, and microbial activity decreased with increased concentrations of crude oil. This phenomenon can be easily explained by the fact that the microbial metabolic activity had been affected owing to an increase in carbon sources and an imbalance in the soil nutrient ratio followed by an increase in the crude oil concentration in soil. The microbes in both crude oil-contaminated and uncontaminated soil were more likely to use carbon sources such as carbohydrates and polymers on the Biolog plates. Microbes from crude oil-contaminated soil used less of the available carbon sources and showed lower metabolic activity than microbes from the uncontaminated soil. This indicated that soil microbes adapted to the crude oil-contaminated environment by adjusting the microbial community structure, and a correlation was observed between the soil microbial community structure and soil microbial growth. The principal component analyses results revealed a significant difference (P <0.01) in soil microbial community structure between uncontaminated and crude oil-contaminated soils. The differences mostly related to the use of carbohydrates as the dominant carbon source and then carboxylic acids and amino acids. The variation in the canonical variable (discrete value) increased with increasing soil crude oil content, however, the stability of the soil microbial community structure decreased. This indicated that the crude oil pollutant destroyed the original soil ecological environment. The diversity of microbial community, as indicated by Shannon (H), McIntosh (U), and Simpson (1/ D) indices, was significantly different in crude oil-contaminated soil (P < 0.01) compared with uncontaminated soil. H and U values were lower in crude oil- contaminated soil than in uncontaminated soil, and 1/ D was higher in crude oil-contaminated soil than in uncontaminated soil. This phenomenon was likely due to the stimulating effect of certain levels of crude oil on the growth of the dominant microbial community. The findings stated above provide a basis for bioremediation of oil-contaminated soil in the Loess Plateau in northern Shaanxi. These results are especially important because they indicated that the soil in the Loess Plateau in northern Shaanxi shows good potential for bioremediation, and crude oil contamination in the soil could be degraded by indigenous microbes with the addition of nitrogen and phosphorus. An additional benefit is that it leads to an improved evaluation of the bioremediation potential of the indigenous microbial consortia. © 2015 Ecological Society of China. All Rights Reserved.


Hu T.,Northwest Agriculture and Forestry University | Gu J.,Northwest Agriculture and Forestry University | Zhen L.,Northwest Agriculture and Forestry University | Zhen L.,Shaanxi Province Microbiology Institute | And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014

A bacterium strain, which prove to be highly effective in phenol degrading, was isolated from soil contaminated with oil in Jingbian oilfield of Northern Shaanxi by using enrichment culture method with phenol as a sole carbon source. The bacterium was named ad049 and identified as Rhodococcus on the basis of the morphological characterizations, physiological and biochemical identification, and alignment analysis of the 16S rDNA sequence. Effects of inoculation quantity of ad049, pH, temperature, and concentration of phenol as a substrate on bacterial growth and the efficiency of ad049 on phenol degradation were also investigated by shaker culture method, and dehydrogenase and catechol dioxygenase were determined as well. Results showed that the ad049 had a strong biodegradation capability for phenol. It degraded 99% of the phenol in a concentration of 1000 mg/ L in 24 hours under the incubating condition of 30°C, pH 8, and 5% of ad049 inoculation. The degradation process could be described with zero order kinetics equation with the k0 and R2 values of 41.51and 0.96, respectively. The degradation of phenol by ad049 might be achieved largely by 1,2-dioxygenase for ortho ring opening of benzene, and partly by catechol 2,3-dioxygenase for meta-cleavage.


Wan Y.,Shaanxi Province Microbiology Institute | Zi J.,Shaanxi Province Microbiology Institute | Zhang K.,Shaanxi Province Microbiology Institute | Zhang Z.,Shaanxi Province Microbiology Institute | And 3 more authors.
Shengwu Gongcheng Xuebao/Chinese Journal of Biotechnology | Year: 2012

To screen an efficient recombinant Staphylococcus aureus protein A (SpA) for preparing matrix for affinity purification of immunoglobulin G (IgG), a genetic engineering approach was used to obtain monomer, two, three, four and five tandem repeats genes of the Z domain of SpA, then the genes were cloned into expression vector pET-22b and subsequently expressed in Escherichia coli BL21 (DE3). After induction with lactose, the target proteins were purified by Ni2+affinity chromatography. The proteins with two, three, four and five tandem repeats of the Z domain were then coupled to CNBr-activated Sepharose 4B as an affinity chromatography matrix for affinity purification of human IgG. Furthermore, the differences in protein yield and IgG-binding capacity at different recombinant proteins were analyzed. The target proteins with monomer and tandem repeats of the Z domain had an effective expression in the genetic engineering bacteria. IgG could be specifically absorbed from human plasma by affinity chromatography. The protein yield and amount of IgG absorption of per mole protein could be improved by increasing the tandem repeats number of the Z domain. Compared with other tandem repeats, four tandem repeats of the Z domain exhibited more protein yield (160 mg/10 g wet cells) and higher level of IgG absorption (34.4 mg human IgG/mL gel). Therefore, four tandem repeats of the Z domain is more suitable for preparing matrix for affinity purification of IgG. ©2012 by the institute of Microbiology.


PubMed | Shaanxi Province Microbiology Institute
Type: Journal Article | Journal: Sheng wu gong cheng xue bao = Chinese journal of biotechnology | Year: 2013

To screen an efficient recombinant Staphylococcus aureus protein A (SpA) for preparing matrix for affinity purification of immunoglobulin G (IgG), a genetic engineering approach was used to obtain monomer, two, three, four and five tandem repeats genes of the Z domain of SpA, then the genes were cloned into expression vector pET-22b and subsequently expressed in Escherichia coli BL21 (DE3). After induction with lactose, the target proteins were purified by Ni2+ affinity chromatography. The proteins with two, three, four and five tandem repeats of the Z domain were then coupled to CNBr-activated Sepharose 4B as an affinity chromatography matrix for affinity purification of human IgG. Furthermore, the differences in protein yield and IgG-binding capacity at different recombinant proteins were analyzed. The target proteins with monomer and tandem repeats of the Z domain had an effective expression in the genetic engineering bacteria. IgG could be specifically absorbed from human plasma by affinity chromatography. The protein yield and amount of IgG absorption of per mole protein could be improved by increasing the tandem repeats number of the Z domain. Compared with other tandem repeats, four tandem repeats of the Z domain exhibited more protein yield (160 mg/10 g wet cells) and higher level of IgG absorption (34.4 mg human IgG/mL gel). Therefore, four tandem repeats of the Z domain is more suitable for preparing matrix for affinity purification of IgG.

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