Induction of Microbial Oxidative Stress as a New Strategy to Enhance the Enzymatic Degradation of Organic Micropollutants in Synthetic Wastewater.

Organic micropollutants (OMPs) are pervasive anthropogenic contaminants of receiving waters where they can induce various adverse effects to aquatic life. Their ubiquitous environmental occurrence is primarily attributed to discharge from wastewater treatment plants due to incomplete removal by common biological wastewater treatment processes. Here, we assess a new strategy for promoting the degradation of six representative OMPs (i.

Using carbon substrate as a selection pressure to enhance the potential of aerobic granular sludge microbial communities for removing contaminants of emerging concern.

The ability of aerobic granular sludge (AGS) technology to biotransform contaminants of emerging concern (CECs) is largely unknown. AGS supplemented with either acetate, 2-propanol, glycerol, or a 1:1:1 mixture of all three, were cultivated to investigate the link between carbon supplements and biotransformation of six CECs. Carbon substrate had a significant effect on the microbial community composition, as assessed by 16S rRNA gene sequence analyses.

Modulation of Nitrous Oxide (NO) Accumulation by Primary Metabolites in Denitrifying Cultures Adapting to Changes in Environmental C and N.

Metabolomics provides insights into the actual physiology of cells rather than their mere "potential", as provided by genomic and transcriptomic analysis. We investigate the modulation of nitrous oxide (NO) accumulation by intracellular metabolites in denitrifying bacteria using metabolomics and genome-based metabolic network modeling. Profiles of metabolites and their rates of production/consumption were obtained for denitrifying batch cultures under four conditions: initial COD:N ratios of 11:1 and 4:1 with and without nitrite spiking (28 mg-N L).

Nitrosomonas europaea adaptation to anoxic-oxic cycling: Insights from transcription analysis, proteomics and metabolic network modeling.

In suboxic or anoxic environments, nitrous oxide (NO) can be produced by ammonia oxidizing bacteria (AOB) as a potent greenhouse gas. Although NO producing inventory and pathways have been well-characterized using archetypal AOB, there is little known about their adaptive responses to oxic-anoxic cycling, which is a prevalent condition in soil, sediment, and wastewater treatment bioreactors. In this study, cellular responses of Nitrosomonas europaea 19718 to sustained anoxic-oxic cycling in a chemostat bioreactor were evaluated at transcriptomic, proteomic, and fluxomic levels.

Metabolic Network Modeling of Microbial Interactions in Natural and Engineered Environmental Systems.

We review approaches to characterize metabolic interactions within microbial communities using Stoichiometric Metabolic Network (SMN) models for applications in environmental and industrial biotechnology. SMN models are computational tools used to evaluate the metabolic engineering potential of various organisms. They have successfully been applied to design and optimize the microbial production of antibiotics, alcohols and amino acids by single strains.

Clarifying the regulation of NO/N2O production in Nitrosomonas europaea during anoxic-oxic transition via flux balance analysis of a metabolic network model.

The metabolic mechanism regulating the production of nitric and nitrous oxide (NO, N2O) in ammonia oxidizing bacteria (AOB) was characterized by flux balance analysis (FBA) of a stoichiometric metabolic network (SMN) model. The SMN model was created using 51 reactions and 44 metabolites of the energy metabolism in Nitrosomonas europaea, a widely studied AOB. FBA of model simulations provided estimates for reaction rates and yield ratios of intermediate metabolites, substrates, and products.

ORGANIC CARBON SUPPLEMENTATION OF STERILIZED MUNICIPAL WASTEWATER IS ESSENTIAL FOR HETEROTROPHIC GROWTH AND REMOVING AMMONIUM BY THE MICROALGA CHLORELLA VULGARIS(1).

Heterotrophic growth of the microalga Chlorella vulgaris Beij. in synthetic as well as sterilized municipal wastewater of a nonindustrialized city was measured. The city wastewater contained high levels of ammonium and nitrate, medium levels of phosphate, and low levels of nitrite and organic molecules and could not support heterotrophic growth of C.

Heterotrophic cultures of microalgae: metabolism and potential products.

This review analyzes the current state of a specific niche of microalgae cultivation; heterotrophic growth in the dark supported by a carbon source replacing the traditional support of light energy. This unique ability of essentially photosynthetic microorganisms is shared by several species of microalgae. Where possible, heterotrophic growth overcomes major limitations of producing useful products from microalgae: dependency on light which significantly complicates the process, increase costs, and reduced production of potentially useful products.