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Stimulation impact of electric currents on heterotrophic denitrifying microbial viability and denitrification performance in high concentration nitrate-contaminated wastewater

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Journal of Environmental Sciences 2019年第3期31卷 363-371页

作者： Shuang Tong Hengyuan Liu Chuanping Feng Nan Chen Yan Zhao Baocai Xu Jiamin Zhao Ming Zhu Beijing Key Laboratory of Meat Processing Technology China Meat Research Center School of Food and Chemical Engineering Beijing Technology and Business University School of Water Resources and Environment China University of Geosciences (Beijing)

Electric current stimulation has been shown to have a positive influence on heterotrophic denitrifying microbial viability and has the potential to improve wastewater denitrification performance. This study investigated the effects of varying current densities on microbial activity and NO_3^- removal efficiency under heterotrophic ***_3^-removal rate was highest at an applied current density of 400 mA/m^2. However, the optimum removal efficiency of total inorganic nitrogen(TIN; 99%) was achieved when the current density was fixed at 200 m A/m^2. Accumulation of NH_4^+-N and NO_2^--N byproducts were also minimized at this current density. The activity of heterotrophic denitrifying microorganisms was much higher at both 200 and 400 mA/m^2. Moreover, the average adenosine-5′-triphosphate(ATP)content(an indicator of cell metabolism) at a current density of 1600 mA/m^2 was lower than that under no current, indicating heterotrophic denitrifying microbial activity can be inhibited at high current densities. Hence, direct electrical stimulation on the activity of heterotrophic denitrifying microorganisms in the developed system should be lower than 1600 mA/m^2. This study improves the understanding of electric current influence on heterotrophic denitrifying microorganisms and promotes the intelligent application of direct electrical stimulation on wastewater treatment processes.

关键词： Direct electrical stimulation Nitrate removal Denitrification heterotrophic microbial activity Current density Wastewater treatment

Terrestrial dissolved organic carbon consumption by heterotrophic bacterioplankton in the Huanghe River estuary during water and sediment regulation

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Journal of Oceanology and Limnology 2019年第3期37卷 1062-1070页

作者： ZHANG Mingliang YU Guanglei WANG Fei LI Bin HAN Huizong QI Zhanhui WANG Tengteng Shandong Province Key Laboratory of Restoration for Marine Ecology Shandong Marine Resource and Environment Research InstituteYantai 264006China Guangdong Provincial Key Laboratory of Fishery Ecology and Environment South China Sea Fishery Research InstituteChinese Academy of Fishery SciencesGuangzhou 510300China

Nearly 20%–50% of the annual terrestrial dissolved organic carbon(DOC)from the Huanghe(Yellow)River was transported to the estuary during the 5-14d of water and sediment *** concentration of DOC increased sharply during the period of water and sediment regulation,which may promote the terrestrial DOC consumption by heterotrophic *** and sediment regulation provides an ideal condition for the study of terrestrial DOC consumption by heterotrophic bacterioplankton when terrestrial DOC increases sharply in rainy season,which may help to seek the fates of terrestrial DOC in the estuaries and *** this study,the concentration and stable isotope of DOC,the biomass,growth,and respiration of heterotrophic bacterioplankton were *** the study,we found both average percent contribution of terrestrial DOC to the DOC pool and Contribution of terrestrial DOC to the carbon composition of heterotrophic bacterioplankton decreased as distance from the river mouth increased off shore,which was deceased from(39.2±4.0)%,(37.5±4.3)%to(30.3±3.9)%,(28.2±3.9)%respectively.255-484μg C/(L·d)terrestrial DOC was consumed by heterotrophic *** 29%-45%terrestrial DOC consumed by heterotrophic bacterioplankton releasing as CO2 by *** with tropical estuary,terrestrial DOC consumed by heterotrophic bacterioplankton was lower in temperate estuary(this study).Temperature may limit the consumption of terrestrial DOC by heterotrophic bacterioplankton.

关键词： terrestrial dissolved organic carbon heterotrophic bacterioplankton carbon stable isotope biogeochemical cycles

Hydrobiological variables as a regulatory factor on the abundance of heterotrophic flagellates in an urban pond

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Journal of Oceanology and Limnology 2019年第3期37卷 1030-1036页

作者： BEGUM Moni JEWEL Md.Abu Sayed HAQUE Md.Ayenuddin KHATUN Mst.Samsad Department of Fisheries Faculty of Agriculture University of Rajshahi

The seasonal abundance of flagellates has been monitored over a period of 1 year from December 2013 to November 2014(divided into 4 conjugative seasons namely winter,spring,summer,and autumn)in an experimental pond located in Rajshahi City Corporation area,*** our knowledge,this study is the fi rst to shed light on the occurrence and possible interrelationships among heterotrophic flagellates(HF),bacteria and zooplankton in Bangladesh and the result obtained by this study will be beneficial for similar water ecosystem all over the *** methods were used to determine the prescribed hydrological parameters and zooplankton cell *** HF abundance(14 346.00 cells/mL)was found in the spring and the minimum(5 215.00 cells/mL)occurred in the *** to HF,significantly(P<0.05)higher zooplankton abundance was found during the winter(782.00±47.62 cells/mL)and the lowest value was found in the autumn(448.00±39.15 cells/mL).Whereas similar to the HF,total bacterial abundance was significantly higher during the spring((2.25±1.05)×10^5 cells/mL)and lower in the summer((0.79±0.06)×10^5 cells/mL).Multivariate analyses(ANOSIM and MDS)have shown significant seasonal differences for cell numbers where MDS ordination plot and cluster analysis based on similarity in the genera abundance of HF revealed overlapping condition between winter and *** correspondence analysis(CCA)also showed a distinct separation among the genera based on the prevailing hydrological situation and indicated that temperature,pH,BOD5,and NO3^-were the most important environmental variables in determining the observed variation in HF community *** the biological factors,zooplankton showed negative but total bacteria were positively correlated with HF abundance.

关键词： heterotrophic flagellates abundance hydrobiological factors urban pond

Distribution, residence time, autotrophic production, and heterotrophic removal of DOP in the Mirs Bay, northern South China Sea

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Acta Oceanologica Sinica 2019年第8期38卷 17-26页

作者： Huaming Shi Yu Ma Xulu Li Xiaoyong Shi Junxiao Zhang College of Environmental Science and Engineering Ocean University of China Qingdao 266100 China South China Sea Marine Survey and Technology Center Ministry of Natural Resources Guangzhou 510300 China National Marine Hazard Mitigation Service Ministry of Natural Resources Beijing 100194 China

The importance of dissolved organic phosphorus(DOP) as a potential nutrient source for primary producers in marine systems has been recognized for up to eight decades, but currently, the understanding of the biogeochemistry of DOP is in its infancy. In the present study, monthly data between 2000 and 2014 were used to analyze the temporal and spatial distributions of DOP in the Mir Bay, the northern South China Sea. The DOP residence time(TDOP) was also investigated using a simple regression analysis in combination with chlorophyll a(Chl a) measurements while excess DOP(ΔDOP), produced by the biogeochemical processes of autotrophic production and heterotrophic removal, was determined using a two-component mixing mass-balance model in combination with salinity measurements. The results showed that the DOP concentration was(0.017±0.010) mg/L higher in the surface-water compared with the bottom-water and higher in the inner Tolo Harbour and waters adjacent to Shatoujiao compared with the main zone of the bay. Although seasonal changes and annual variability in the DOP were small, the surface DOP concentration was higher in the wet season(April–September)than in the dry season(October–March) due to the impacts of seaward discharges and atmospheric deposition into the bay. Measurement and regression results showed that the DOP release rate from phytoplankton production was about 1.83(gP)/(gChl a) and the TDOP was about 7 d, which implied that the DOP cycle in the bay was rapid. The ΔDOP was calculated from the model to be about 0.000 mg/L in the main zone of the bay and about 0.002 mg/L in the inner Tolo Harbour and waters adjacent to Shaotoujiao, suggesting that the autotrophic production of DOP was almost balanced by the heterotrophic removal in the main zone of the bay and dominated in the inner Tolo Harbour and waters adjacent to Shaotoujiao. In conclusion, the Mirs Bay is very productive and fairly heterotrophic.

关键词： dissolved organic phosphorus temporal and spatial distributions residence time autotrophic production heterotrophic removal Mirs Bay northern South China Sea

Enhanced production of lutein in heterotrophic Chlorella protothecoides by oxidative stress

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Science China(Life Sciences) 2008年第12期51卷 1088-1093页

作者： WEI Dong1, CHEN Feng2, CHEN Gu1, ZHANG XueWu1, LIU LongJun1 & ZHANG Hao3 1 College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China 2 School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China 3 College of Food Sciences, Jiangnan University, Wuxi 214122, China 1. College of Light Industry and Food Sciences South China University of Technology Guangzhou 510640 China 2. School of Biological Sciences The University of Hong Kong Hong Kong SAR China 3. College of Food Sciences Jiangnan University Wuxi 214122 China

The fast growing unicellular green microalgae Chlorella protothecoides has attracted interest as a promising organism for commercial production of a high-value carotenoid, lutein, by heterotrophic fermentation. Effects of two oxidant-forming reactive oxygen species (ROS) on the biomass concen-tration, and yield and content of lutein in batch culture of heterotrophic Chlorella protothecoides were investigated in this study. The addition of 0.1 mmol/L H2O2 and 0.01 mmol/L NaClO plus 0.5 mmol/L Fe2+ to the culture led to the generation of ·OH and enhanced the lutein content from 1.75 to 1.90 and 1.95 mg/g, respectively. The lutein content further increased to 1.98 mg/g when 0.01 mmol/L H2O2 and 0.5 mmol/L NaClO were added to generate 1O2. The maximum yield of lutein (28.5, 29.8 and 31.4 mg/L) and a high biomass concentration (15.0, 15.3 and 15.9 g/L) were also achieved through the above treatments. The results indicated that 1O2 could promote lutein formation and enhance lutein production in hetero-trophic Chlorella protothecoides. Moreover, 1O2 produced from the reaction of H2O2 and NaClO was more effective in enhancing lutein production and reducing biomass loss than ·OH from the reaction of H2O2 or NaClO plus Fe2+.

关键词： Chlorella protothecoides heterotrophic lutein oxidative stress ROS

heterotrophic and Autotrophic Soil Respiration under Simulated Dormancy Conditions

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Open Journal of Forestry 2015年第3期5卷 274-286页

作者： Daniel Beverly Scott Franklin School of Biological Sciences University of Northern Colorado Greeley CO USA Botany Department University of Wyoming Laramie WY USA

Carbon cycling research has increased over the past 20 years, but less is known about the primary contributors to soil respiration (i.e. heterotrophic and autotrophic) under dormant conditions. It is understood that soil CO2 effluxes are significantly lower during the winter of temperate ecosystems and assumed microorganisms dominate efflux origination. We hypothesized that heterotrophic contributions would be greater than autotrophic under simulated dormancy conditions. To test this hypothesis, we designed an experiment with the following treatments: combined autotrophic heterotrophic respiration, heterotrophic respiration, autotrophic respiration, no respiration, autotrophic respiration in vermiculite, and no respiration in vermiculite. Engelmann spruce seedlings and soil substrates were placed in specially designed respiration chambers and soil CO2 efflux measurements were taken four times over the course of a month. Soil microbial densities and root volumes were measured for each chamber after day thirty-three. Seedling presence resulted in significantly higher soil CO2 efflux rates for all soil substrates. Autotrophic respiration treatments were not representative of solely autotrophic soil CO2 efflux due to soil microbial contamination of autoclaved soil substrates;however, the mean autotrophic contributions averaged less than 25% of the total soil CO2 efflux. Soil microorganism communities were likely the primary contributor to soil CO2 efflux in simulated dormant conditions, as treatments with the greatest proportions of microbial densities had the highest soil CO2 efflux rates. Although this study is not directly comparable to field dormant season soil CO2 effluxes of Engelmann spruce forest, as snowpack is not maintained throughout this experiment, relationships, and metrics from such small-scale ecosystem component processes may yield more accurate carbon budget models.

关键词： Dormant Autotrophic Respiration heterotrophic Respiration Dormant Soil CO2 Efflux Soil Respiration Engelmann Spruce

Heterogeneity of heterotrophic Bacteria Dominating in Brackish Lake Shira (Republic of Khakasia, Russia) Subjected to Anthropogenic Impact

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Journal of Water Resource and Protection 2010年第5期2卷 389-395页

作者： Tatiana I. Lobova Yuriy V. Barkhatov Olga V. Salamatina Ludmila Yu. Popova 不详

In this work data on heterogeneity in halotolerance and the resistance to antibiotics of heterotrophic bacteria dominating in Lake Shira (Republic of Khakasia, Russia) were presented. It was established that halotoler-ance of the bacteria is determined by genetic and epigenetic mechanisms. Influence of anthropogenic factor (entering the ecosystem allochthonous bacteria) on the appearance of multiple antibiotic resistance appear-ance by dominating bacterial species is discussed.

关键词： Anthropogenic Impact Antibiotic Resistance Halotolerance heterotrophic Bacteria Heterogeneity

Study on Characteristics in the Removal Process of Ammonia Nitrogen and Nitrate Nitrogen by an Isolated heterotrophic Nitrification-Aerobic Denitrification Strain Rhodococcus Sp.

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Journal of Environmental Protection 2013年第1期4卷 74-79页

作者： Weisi Li Department of chemical engineering China University of Petroleum 266555 Qingdao China

Removal of ammonia nitrogen and nitrate nitrogen by an heterotrophic nitrification-aerobic denitrification strain is an economical and effective method. In this article, a kind of heterotrophic nitrification-aerobic denitrification strain which has aerobic denitrification and heterotrophic nitrification ability was selected, and then was identified as rhodococcus sp. by 16S rRNA sequencing analysis and morphological observation. After that, carbon source utilization and nitrification- denitrification activity of this strain in different C/N, initial nitrogen concentration were studied. In addition, the assimilation and denitrification activities of ammonia and nitrate were also researched under the condition of nitrate and ammonia coexisted in the solution. The results show that the strain can grow in sodium acetate, glucose, sodium succinate and sodium citrate solutions, and it can not survive in sodium oxalate, sucrose and soluble starch solutions. Initial concentration and C/N were important for nitrogen removal rate. This strain can completely remove nitrate/ammonia when nitrate/ammonia concentration was lower than 15 mg l-1/80 mg l-1. the C/N of 10 and of 12 were the optimum C/N ratio in the nitrate and ammonia removal process respectively. pH value rose up sharply in the denitrification process and it increased relatively slowly in the nitrification process, which shows that pH is one of the most important factor inhibiting the denitrification removal process. Nitrite concentration was much higher in denitrification process than in nitrification process. In addition, this strain gave priority to utilizing ammonia as nitrogen source when ammonia and nitrate coexisted in the solution.

关键词： Aerobic denitrification heterotrophic nitrification Rhodococcus sp. Nitrogen removal

Evaluation of Oil Producing Potential of a New Isolate—<i>Chlorella lewinii</i>SUB3545914 for Biodiesel Production under heterotrophic Cultivation

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Journal of Sustainable Bioenergy Systems 2018年第3期8卷 67-81页

作者： Innocent Okonkwo Ogbonna James Chukwuma Ogbonna Department of Microbiology University of Agriculture Makurdi Nigeria Department of Microbiology University of Nigeria Nsukka Nigeria

Microalgae with high oil productivities are most desired in biodiesel production. Chlorella lewinii SUB3545914, was isolated and assessed for its growth rates, lipid productivities and fatty acid profiles under heterotrophic cultivation. The alga was isolated after enrichment in BG-11 medium (pH = 7.3) under a light intensity of approximately 17.5 μE·m-2·s-1 at 30°C ± 2°C. In addition to morphology, polymerase chain reaction (PCR) and metagenomics were used for isolate identification. The DNA was sequenced and multiple sequence alignment of the BLASTED results revealed 95% similarity to Chlorella lewinii. Maximum growth (3.15 ± 0.06 g·L-1), lipid content (44.0%) and lipid volumetric productivities (118.80 ± 3.02 mg·L-1·day-1) in glucose supplemented media were more appreciable in comparison with the glycerol counterparts. Similarly, the highest growth (2.03 ± 0.68 g·L-1), lipid content (31.47%) and lipid productivities (47.21 ± 2.08 mg·L-1·day-1) in glycerol supplemented media were more than those got under autotrophic cultivation. Chlorophyll contents did not vary remarkably in heterotrophic cultures. The major fatty acids obtained by Gas Chromatography Mass Spectrometry (GC-MS) were oleic and Octadecanoic acids for all the culture conditions. Chlorella lewinii is appropriate for accumulating lipids for biodiesel under heterotrophic cultivation on glucose because of high lipid volumetric productivities.

关键词： Biodiesel Chlorella lewinii Fatty Acid Contents heterotrophic Culture Microalgal Biomass Content Microalgal Lipid Accumulation