https://www.cell.com/trends/biotechnology/pdf/S0167-7799(06)00099-0.pdf

Environmental biocatalysis: from remediation with enzymes to novel green processes

In situ bioremediation of monoaromatic pollutants in groundwater : A review

The still poorly explored world of microbial functioning is about to be uncovered by a combined application of old and new technologies. Bacteria, especially, are still in the dark with respect to their phylogenetic affiliations as well as their metabolic capabilities and functions. However, with the advent of sophisticated flow cytometric and cell sorting technologies in microbiological labs, there is now the possibility to gain this knowledge at the single-cell level without cumbersome cultivation approaches. Cytometry also facilitates the understanding of physiological diversity in seemingly likewise acting populations. Both individuality and diversity lead to the complex and concerted actions of microbial consortia. This review provides an overview of the state of the art in the field. It deals with the handling of microorganisms from the very beginning (i.e. sampling, and detachment and fixation procedures) and goes on to discuss the pitfalls and problems in analysing cells without any further treatment. If information cannot be gained by specific staining procedures, phylogenetic technologies, transcriptomic and proteomic approaches may be options for achieving advanced insights. All in all, flow cytometry will be a mediator technology to gain a deeper insight into the heterogeneity of populations and the functioning of microbial communities.

Functional single-cell analyses: flow cytometry and cell sorting of microbial populations and communities.

Wetlands as large-scale nature-based solutions : Status and challenges for research, engineering and management

Rapid industrialization and population explosion has resulted in the generation and dumping of various contaminants into the environment. These harmful compounds deteriorate the human health as well as the surrounding environments. Current research aims to harness and enhance the natural ability of different microbes to metabolize these toxic compounds. Microbial-mediated bioremediation offers great potential to reinstate the contaminated environments in an ecologically acceptable approach. However, the lack of the knowledge regarding the factors controlling and regulating the growth, metabolism, and dynamics of diverse microbial communities in the contaminated environments often limits its execution. In recent years the importance of advanced tools such as genomics, proteomics, transcriptomics, metabolomics, and fluxomics has increased to design the strategies to treat these contaminants in ecofriendly manner. Previously researchers has largely focused on the environmental remediation using single omics-approach, however the present review specifically addresses the integrative role of the multi-omics approaches in microbial-mediated bioremediation. Additionally, we discussed how the multi-omics approaches help to comprehend and explore the structural and functional aspects of the microbial consortia in response to the different environmental pollutants and presented some success stories by using these approaches.

Understanding and Designing the Strategies for the Microbe-Mediated Remediation of Environmental Contaminants Using Omics Approaches.

Natural attenuation and enhanced bioremediation of organic contaminants in groundwater.

A field-scale fixed bed bioreactor was used to successfully treat an MTBE-contaminated aquifer in North Hollywood, CA without requiring inoculation with introduced bacteria. Native bacteria from the MTBE-impacted aquifer rapidly colonized the bioreactor, entering the bioreactor in the contaminated groundwater pumped from the site, and biodegraded MTBE with greater than 99 % removal efficiency. DNA sequencing of the 16S rRNA gene identified MTBE-degrading bacteria Methylibium petroleiphilum in the bioreactor. Quantitative PCR showed M. petroleiphilum enriched by three orders of magnitude in the bioreactor above densities pre-existing in the groundwater. Because treatment was carried out by indigenous rather than introduced organisms, regulatory approval was obtained for implementation of a full-scale bioreactor to continue treatment of the aquifer. In addition, after confirmation of MTBE removal in the bioreactor to below maximum contaminant limit levels (MCL; MTBE = 5 μg L−1), treated water was approved for reinjection back into the aquifer rather than requiring discharge to a water treatment system. This is the first treatment system in California to be approved for reinjection of biologically treated effluent into a drinking water aquifer. This study demonstrated the potential for using native microbial communities already present in the aquifer as an inoculum for ex-situ bioreactors, circumventing the need to establish non-native, non-acclimated and potentially costly inoculants. Understanding and harnessing the metabolic potential of native organisms circumvents some of the issues associated with introducing non-native organisms into drinking water aquifers, and can provide a low-cost and efficient remediation technology that can streamline future bioremediation approval processes.

/pdf/successful-treatment-of-an-mtbe-impacted-aquifer-using-a-3kjkm3jt9w.pdf

Successful treatment of an MTBE-impacted aquifer using a bioreactor self-colonized by native aquifer bacteria

Lactuca sativa (commonly referred to as lettuce) is one of the most popular grown hydroponic crops. While other fertilizer rate work has been conducted on lettuce, the impact of each element has not been evaluated independently or by determining adequate foliar tissue concentrations when all nutrients are plant-available. This study explores the impact that macronutrients have on the growth and yield of lettuce at different stages of the production cycle. Additionally, this study explores the adequate nutrient rates by regressing nutrient curves to find the concentration of each element that corresponds to optimal growth. Plants were grown under varying macronutrient concentrations (0, 8, 16, 32, 64, and 100%) utilizing the concentrations of a modified Hoagland’s solution based on 150 mg·L−1 N. Lettuce plants were grown in a silica sand culture and received a nutrient solution in which a single element was altered. Visual symptomology was documented, and leaf tissue mineral nutrient concentrations and biomass were measured at Weeks 3, 6, and 8 after transplant. Optimal elemental leaf tissue concentration and biomass varied by macronutrient rates and weeks of growth. Nitrogen rate produced a linear increase in total plant dry weight, but foliar N followed a quadratic plateau pattern. Other elements, such as phosphorus, potassium, and magnesium, produced distinct total plant dry weight plateaus despite increasing fertility concentrations. These results demonstrate that fertility recommendation can be lowered for nutrients where higher rates do not result in higher plant biomass or foliar nutrient concentrations.

https://www.mdpi.com/2311-7524/8/11/1075/pdf?version=1668586049

Impact of Macronutrient Fertility on Mineral Uptake and Growth of Lactuca sativa ‘Salanova Green’ in a Hydroponic System

ABSTRACT Zinc (Zn) and copper (Cu) are necessary micronutrients for crop production. However, excess Zn and Cu applied through land application of manures can result in Zn and Cu toxicity, reducing yields. With many integrators and little information on the formulation of poultry feeds in North Carolina (NC), it is difficult to predict the fractionation of Zn and Cu in litters generated at facilities, as the form of Zn and Cu determines mobility and bioavailability. Therefore, statewide data from the NC Department of Agriculture and Consumer Services was analyzed to determine regional variation of total Zn and Cu. The results showed a significant effect of the region on the total Zn and Cu among the three production regions in the state. Additionally, 11 broilers and broiler breeder litter samples were analyzed to determine the distribution of Zn and Cu in acid soluble, reducible, oxidizable, and residual fractions. Total Zn and Cu averaged 675 mg/kg and 629 mg/kg, respectively. There was a significant interaction between the region and Zn concentration in the fractions. However, there was no region interaction when converted to a percentage of the sum of the fractions, indicating Zn partitions similarly across a wide range of concentrations and 37%, 40%, 21%, and 0.6% was found in the acid soluble, reducible, oxidizable, and residual fractions, respectively. Region did not have an effect on Cu fractionation, with 26%, 8%, 67%, and 2% of Cu in the acid-soluble, reducible, oxidizable, and residual fractions, respectively. Results indicate greater bioavailability and mobility potential for Zn as compared to Cu.

Kristin A. Hicks

Papers

Natural attenuation and enhanced bioremediation of organic contaminants in groundwater.

Successful treatment of an MTBE-impacted aquifer using a bioreactor self-colonized by native aquifer bacteria

Impact of Macronutrient Fertility on Mineral Uptake and Growth of Lactuca sativa ‘Salanova Green’ in a Hydroponic System

Distribution and Fractionation of Zinc and Copper in Poultry Litters Across North Carolina