Environmental Consortium Research Articles

Dose–Response Effect of Nitrogen on Microbial Community during Hydrocarbon Biodegradation in Simplified Model System

Knowledge about the influence of C:N ratio on the biodegradation process of hydrocarbon compounds is of significant importance in the development of biostimulation techniques. The purpose of this study was to assess the impact of nitrogen compounds on the environmental consortium during the process of biological decomposition of hydrocarbons. The experimental variants represented low, moderate, and excessive biostimulation with nitrogen compounds. The metabolic activity of the consortium was tested using the flow cytometry technique. The efficiency of the biodegradation of hydrocarbons of the consortium, based on the gas chromatography method, and metapopulation changes, based on the analysis of V4 16srRNA sequencing data, were assessed. The results of the research confirm the positive effect of properly optimized biostimulation with nitrogen compounds on the biological decomposition of polycyclic aromatic hydrocarbons. The negative impact of excessive biostimulation on the biodegradation efficiency and metabolic activity of microorganisms is also proven. Low resistance to changes in the supply of nitrogen compounds is demonstrated among the orders Xanthomonadales, Burkholderiales, Sphingomonadales, Flavobacteriales, and Sphingobacteriales. It is proven that quantitative analysis of the order of Rhizobiales, characterized by a high-predicted potential for the decomposition of polycyclic aromatic hydrocarbons, may be helpful during biostimulation optimization processes in areas with a high nitrogen deficiency.

Bioreactor production of 2,3-butanediol by Pantoea agglomerans using soybean hull acid hydrolysate as substrate.

Production of 2,3-butanediol (2,3-BD) by Pantoea agglomerans strain BL1 was investigated using soybean hull hydrolysate as substrate in batch reactors. The cultivation media consisted of a mixture of xylose, arabinose, and glucose, obtained from the hemicellulosic fraction of the soybean hull biomass. We evaluated the influence of oxygen supply, pH control, and media supplementation on the growth kinetics of the microorganism and on 2,3-BD production. P. agglomerans BL1 was able to simultaneously metabolize all three monosaccharides present in the broth, with average conversions of 75% after 48h of cultivation. The influence of aeration conditions employed demonstrated the mixed acid pathway of 2,3-BD formation by enterobacteria. Under fully aerated conditions (2 vvm of air), up to 14.02gL-1 of 2.3-BD in 12h of cultivation were produced, corresponding to yields of 0.53gg-1 and a productivity of 1.17gL-1h-1, the best results achieved. These results suggest the production potential of 2,3-BD by P. agglomerans BL1, which has been recently isolated from an environmental consortium. The present work proposes a solution for the usage of the hemicellulosic fraction of agroindustry biomasses, carbohydrates whose utilization are not commonly addressed in bioprocess.

Heavy Metals as a Factor Increasing the Functional Genetic Potential of Bacterial Community for Polycyclic Aromatic Hydrocarbon Biodegradation.

The bioremediation of areas contaminated with hydrocarbon compounds and heavy metals is challenging due to the synergistic toxic effects of these contaminants. On the other hand, the phenomenon of the induction of microbial secretion of exopolysaccharides (EPS) under the influence of heavy metals may contribute to affect the interaction between hydrophobic hydrocarbons and microbial cells, thus increasing the bioavailability of hydrophobic organic pollutants. The purpose of this study was to analyze the impact of heavy metals on the changes in the metapopulation structure of an environmental consortium, with particular emphasis on the number of copies of orthologous genes involved in exopolysaccharide synthesis pathways and the biodegradation of hydrocarbons. The results of the experiment confirmed that the presence of heavy metals at concentrations of 50 mg·L−1 and 150 mg·L−1 resulted in a decrease in the metabolic activity of the microbial consortium and its biodiversity. Despite this, an increase in the biological degradation rate of polycyclic aromatic hydrocarbons was noted of 17.9% and 16.9%, respectively. An assessment of the estimated number of genes crucial for EPS synthesis and biodegradation of polycyclic aromatic hydrocarbons confirmed the relationship between the activation of EPS synthesis pathways and polyaromatic hydrocarbon biodegradation pathways. It was established that microorganisms that belong to the Burkholderiales order are characterized by a high representation of the analyzed orthologs and high application potential in areas contaminated with heavy metals and hydrocarbons.

Production of 2,3-butanediol by Klebsiella pneumoniae BLh-1 and Pantoea agglomerans BL1 cultivated in acid and enzymatic hydrolysates of soybean hull.

We investigated the production of 2,3-butanediol by two enterobacteria isolated from an environmental consortium, Klebsiella pneumoniae BLh-1 and Pantoea agglomerans BL1, in a bioprocess using acid and enzymatic hydrolysates of soybean hull as substrates. Cultivations were carried out in orbital shaker under microaerophilic conditions, at 30°C and 37°C, for both bacteria. Both hydrolysates presented high osmotic pressures, around 2,000 mOsm/kg, with varying concentrations of glucose, xylose, and arabinose. Both bacteria were able to grow in the hydrolysates, at both temperatures, and they efficiently converted sugars into 2,3-butanediol, showing yields varying from 0.25 to 0.51 g/g of sugars and maximum 2,3-butanediol concentrations varying from 6.4 to 21.9 g/L. Other metabolic products were also obtained in lower amounts, notably ethanol, which peaked at 3.6 g/L in cultures using the enzymatic hydrolysate at 30°C. These results suggest the potential use of these recently isolated bacteria to convert lignocellulosic biomass hydrolysates into value-added products.

Phenol Biodegradation and Metal Removal by a Mixed Bacterial Consortium

ABSTRACTThis paper reports the tolerance and biodegradation of phenol by a heavy metal–adapted environmental bacterial consortium, known as consortium culture (CC). At the highest tolerable phenol concentration of 1200 mg/L, CC displayed specific growth rate of 0.04 h−1, phenol degradation rate of 6.11 mg L−1 h−1 and biomass of 8.45 ± 0.35 (log10 colony-forming units [CFU]/ml) at the end of incubation. Phenol was degraded via the ortho-cleavage pathway catalyzed by cathechol-1,2-dioxygenase with specific activity of 0.083 (µmol min−1 mg−1 protein). The different constituent bacterial isolates of CC preferentially grow on benzene, toluene, xylene, ethylbenzene, cresol, and catechol, suggesting a synergistic mechanism involved in the degradation process. Microtox assay showed that phenol degradation was achieved without producing toxic dead-end metabolites. Moreover, lead (Pb) and cadmium (Cd) at the highest tested concentration of 1.0 and 0.1 mg/L, respectively, did not inhibit phenol degradation by CC. Simultaneous metal removal during phenol degradation was achieved using CC. These findings confirmed the dual function of CC to degrade phenol and to remove heavy metals from a mixed-pollutant medium.

Cellulose fermentation by Clostridium thermocellum and a mixed consortium in an automated repetitive batch reactor

An automated repetitive batch fermentation system was developed to facilitate the study of microbial cellulose utilization. The system was operated with Avicel as the carbon source and either Clostridium thermocellum ATCC 27405 or a consortium enriched from compost as inocula. Multiple cycles of growth medium addition, incubation, and medium removal were performed with each inoculum. Removal and addition of media were automatically initiated when CO2 production fell to 90% of the cycle's peak. A strong correlation was observed between CO2 production and cellulose consumption, suggesting that the online signal was a good proxy for substrate utilization. Both cultures exhibited accelerated substrate utilization and a decrease in cycle time. About the same number of cycles was required to reach maximum CO2 production for both cultures. Notably, the magnitudes of the maximum CO2 production rate and cycle times were very similar for both C. thermocellum in pure culture and an environmental consortium.

Beyond the Bench: Flagging Environmental Health Awareness on Beaches

During the summer months, folks flock to the beach to enjoy the combined pleasures of sun and sea. Smart beachgoers know that before they take a dip, they should check whether any warning flags are flying, indicating hazardous conditions such as rip currents or the presence of jellyfish. Now, Galveston swimmers can look for a new “environmental alert” flag. The new flag warns beachgoers of air and weather conditions that could pose a health threat, especially to particularly vulnerable populations such as asthmatics, the elderly, and people with heart or lung disease. The new flag reflects the translation of research findings into concrete community health education by investigators in the Asthma Pathogenesis Core of the University of Texas Medical Branch (UTMB) and codirectors of the Asthma Community Outreach and Education Core (COEC), in partnership with the Galveston Sheriff’s Office Beach Patrol, the Galveston Park Board of Trustees, and the Texas Commission on Environmental Quality. Three years ago, investigators Sharon A. Petronella and Edward G. Brooks initiated the Gulf Coast Study of Urban Air Quality and Respiratory Function (GC SURF) to study pulmonary function in a cohort of lifeguards in Galveston. During the summers of 2003 through 2005 they collected pulmonary effects data on the GC SURF cohort by using portable spirometers, which measure the amount of inhaled and exhaled air. This allowed them to evaluate exposure to and effects of air pollutants and weather conditions including nitric oxide, nitrogen dioxide, ozone, particulate matter, wind speed, outdoor temperature, relative humidity, and solar radiation. The data gathered helped the investigators determine particular times of day when changes in air quality could affect breathing health. Now, whenever the Texas Commission on Environmental Quality deems that air quality conditions exist that might affect vulnerable populations, the city’s 26 lifeguard towers and 7 free-standing beach stations deploy an orange flag and display information on posters and in brochures describing the particular environmental issues and guidelines for protecting health. The program, which the COEC believes to be the first in the nation to enlist lifeguard participation in an environmental health public warning system, provides educational materials on ozone, fine particulates, and, as needed, red tide. The group has now also developed a partnership with the Galveston County Health District to display the environmental flags at each tower when water quality is less than optimal. Petronella says the alert program is the result of a true collaborative effort between the partner organizations and is a solid indication of what can happen when a community comes together. The developers, who hope the orange flag alert program can be used as a model for other beaches, presented it at the annual meeting of the U.S. Lifesaving Association in Galveston in 2004. In addition to the GC SURF flag alert program, the Asthma Pathogenesis Core of the UTMB COEC is also involved in other projects that focus on building connections between research, education, and community health. One of these, the Texas Emergency Department Asthma Surveillance Project, is a collaborative effort coordinated by Charles Macias of Baylor College of Medicine that links the databases of Baylor and three other Texas hospitals to track asthma-related emergency room visits. The results will aid in the development of an educational intervention program. Another project, Communities Organized Against Asthma and Lead, is an environmental justice consortium combining the educational outreach efforts of the COEC with community social services and health care providers. COEC investigators are also involved in a school asthma surveillance project. “As researchers involved in the UTMB NIEHS Center Asthma Pathogenesis Core, we work in and with our community to identify problems and potential solutions related to our environment,” says Petronella. “Our COEC, however, allows us to take our work one crucial step further––by actually assisting the community with education, intervention, and development of policies that will effect positive change in the health of our residents and all visitors to our part of the Gulf Coast.” In essence, Petronella says, the COEC forms the bridge from basic science to the public. “This is essential to our success,” she adds, “since the key to any public health research program is the use to which the data are put.”

Biomodification of Coal to Remove Mercury

A biological process for removal of mercury from coal is under investigation. Iron and sulfur oxidizing bacteria have previously been used for desulfurization of coal and for mineral mining. We have shown that removal of mercury from coal is also possible via the same principles. Two pure cultures, Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans and four environmental consortium samples obtained from an acid mine drainage site were studied for mercury removal from coal. Four different coal samples were included in the study and the preliminary results have shown that up to 20% of the mercury can be removed in batch cultures compared to control. Additional parameters such as media composition and inoculum size were also studied. This is the first report demonstrating successful leaching of mercury from coal using biological treatment.

A “river summer” on the Hudson

Faculty from regional colleges, universities, and research institutes gathered this past summer to teach each other about the Hudson River in New York through a three‐and‐a‐half week field trip called “River Summer.”A pilot field course sponsored by the newly‐established Environmental Consortium of Hudson Valley Colleges and Universities, the program aims to help educators transform the Hudson watershed into an extended laboratory and classroom for multi‐institutional field programs, interdisciplinary research collaborations, and cooperative regional studies. Experiences from this excursion will be used as the foundation for a summer field course for undergraduates.

The analytical environmental immunochemical consortium

The Analytical Environmental Immunochemical Consortium (AEIC) is a relatively new organization, established with the aim of promoting the use of immunochemical methods as recognized analytical tools for food and environmental testing. The members of AEIC include immunoassay kit manufacturers, agricultural and basic chemical manufacturers, immunoassay equipment manufacturers and commercial, government and academic laboratories involved in the research and development of non‐clinical immunochemical technology.