Biofilm mitigation in hybrid chemical-biological upcycling of waste polymers.

Accumulation of plastic waste in the environment is a serious global issue. To deal with this, there is a need for improved and more efficient methods for plastic waste recycling. One approach is to depolymerize plastic using pyrolysis or chemical deconstruction followed by microbial-upcycling of the monomers into more valuable products.

Coexistence of specialist and generalist species within mixed plastic derivative-utilizing microbial communities.

Background: Plastic-degrading microbial isolates offer great potential to degrade, transform, and upcycle plastic waste. Tandem chemical and biological processing of plastic wastes has been shown to substantially increase the rates of plastic degradation; however, the focus of this work has been almost entirely on microbial isolates (either bioengineered or naturally occurring). We propose that a microbial community has even greater potential for plastic upcycling.

Metagenomic Sequencing of Two Cultures Grown on Chemically Deconstructed Plastic Products.

We report the metagenome sequences of two microbial cultures that were grown with chemically deconstructed plastic products as their sole carbon source. These metagenomes will provide insights into the metabolic capabilities of cultures grown on deconstructed plastics and can serve as a starting point for the identification of novel plastic degradation mechanisms.

Deconstructed Plastic Substrate Preferences of Microbial Populations from the Natural Environment.

Over half of the world's plastic waste is landfilled, where it is estimated to take hundreds of years to degrade. Given the continued use and disposal of plastic products, it is vital that we develop fast and effective ways to utilize plastic waste. Here, we explore the potential of tandem chemical and biological processing to process various plastics quickly and effectively.

Killing two birds with one stone: chemical and biological upcycling of polyethylene terephthalate plastics into food.

Most polyethylene terephthalate (PET) plastic waste is landfilled or pollutes the environment. Additionally, global food production must increase to support the growing population. This article explores the feasibility of using microorganisms in an industrial system that upcycles PET into edible microbial protein powder to solve both problems simultaneously.

Study of the Viscosity and Thermal Characteristics of Polyolefins/Solvent Mixtures: Applications for Plastic Pyrolysis.

Plastic pollution is one of the biggest environmental problems that the world is currently facing. Pyrolysis is a frontier technique aimed at converting plastic waste back into virgin-quality resin. However, the transfer of the waste plastic feed into the pyrolysis reactor must be optimized before the process can be upscaled to a continuous process.

A Review of Environmental Life Cycle Assessments of Liquid Transportation Biofuels in the Pan American Region.

Life-cycle assessment (LCA) has been applied to many biofuel and bioenergy systems to determine potential environmental impacts, but the conclusions have varied. Different methodologies and processes for conducting LCA of biofuels make the results difficult to compare, in-turn making it difficult to make the best possible and informed decision. Of particular importance are the wide variability in country-specific conditions, modeling assumptions, data quality, chosen impact categories and indicators, scale of production, system boundaries, and co-product allocation.

Evaluation of hardboard manufacturing process wastewater as a feedstream for ethanol production.

Waste streams from the wood processing industry can serve as feedstream for ethanol production from biomass residues. Hardboard manufacturing process wastewater (HPW) was evaluated on the basis of monomeric sugar recovery and fermentability as a novel feedstream for ethanol production. Dilute acid hydrolysis, coupled with concentration of the wastewater resulted in a hydrolysate with 66 g/l total fermentable sugars.

Feedstock mixture effects on sugar monomer recovery following dilute acid pretreatment and enzymatic hydrolysis.

This study seeks to investigate the effects of biomass mixtures on overall sugar recovery from the combined processes of dilute acid pretreatment and enzymatic hydrolysis. Aspen, a hardwood species well suited to biochemical processing, was chosen as the model species for this study. Balsam, a high-lignin softwood species, and switchgrass, an herbaceous energy crop with high ash content, were chosen as adjuncts.

Effects of dilute acid pretreatment conditions on enzymatic hydrolysis monomer and oligomer sugar yields for aspen, balsam, and switchgrass.

The effects of dilute acid hydrolysis conditions were investigated on total sugar (glucose and xylose) yields after enzymatic hydrolysis with additional analyses on glucose and xylose monomer and oligomer yields from the individual hydrolysis steps for aspen (a hardwood), balsam (a softwood), and switchgrass (a herbaceous energy crop). The results of this study, in the form of measured versus theoretical yields and a severity analysis, show that for aspen and balsam, high dilute acid hydrolysis xylose yields were obtainable at all acid concentrations (0.25-0.

Kinetic characterization for dilute sulfuric acid hydrolysis of timber varieties and switchgrass.

Hydrolysis of four timber species (aspen, balsam fir, basswood, and red maple) and switchgrass was studied using dilute sulfuric acid at 50 g dry biomass/L under similar conditions previously described as acid pretreatment. The primary goal was to obtain detailed kinetic data of xylose formation and degradation from a match between a first order reaction model and the experimental data at various final reactor temperatures (160-190 degrees C), sulfuric acid concentrations (0.25-1.

Characterization of free and immobilized (S)-aminotransferase for acetophenone production.

Enzyme immobilization often improves process economics, but changes in kinetic properties may also occur. The immobilization of a recombinant thermostable (S)-aminotransferase was made by entrapment on calcium alginate-3% (w/v)-and tested with (S)-(-)-(alpha)-methylbenzylamine for acetophenone production. The best immobilization results were obtained for beads of concentration of 10 mg of spray-dried cells (containing recombinant (S)-aminotransferase) per milliliter of sodium alginate bead.

Kinetic characterization and in vitro toxicity evaluation of a luciferase less susceptible to HPV chemical inhibition.

Enzyme-based in vitro toxicity assays are often susceptible to inhibition by test compounds. A mutant luciferase selected to be less susceptible to inhibition by chloroform (CNBLuc03-06) and other high production volume (HPV) chemicals, consisting of three point mutations was created and characterized. The mutant luciferase was less inhibited by chloroform, other HPV chemicals and common surfactant release reagents (Triton-X and SDS) compared to the wild-type.

Creating a mutant luciferase resistant to HPV chemical inhibition by random mutagenesis and colony-level screening.

Firefly luciferase covers a wide range of applications. One common usage of the bioluminescence assay is the measurement of intracellular concentration of adenosine triphosphate (ATP) for cell viability. However, inhibition of the enzyme reaction by chemicals in the assay has so far limited the application of luciferase for high production volume (HPV) chemical testing.

Comparative life-cycle assessments for biomass-to-ethanol production from different regional feedstocks.

This study compares life-cycle (cradle-to-gate) energy consumption and environmental impacts for producing ethanol via fermentation-based processes starting with two lignocellulosic feedstocks: virgin timber resources or recycled newsprint from an urban area. The life-cycle assessment in this study employed a novel combination of computer-aided tools. These tools include fermentation process simulation coupled with an impact assessment software tool for the manufacturing process life-cycle stage impacts.

Green engineering education through a U.S. EPA/academia collaboration.

The need to use resources efficiently and reduce environmental impacts of industrial products and processes is becoming increasingly important in engineering design; therefore, green engineering principles are gaining prominence within engineering education. This paper describes a general framework for incorporating green engineering design principles into engineering curricula, with specific examples for chemical engineering. The framework for teaching green engineering discussed in this paper mirrors the 12 Principles of Green Engineering proposed by Anastas and Zimmerman (Environ.

Industrial applications using BASF eco-efficiency analysis: perspectives on green engineering principles.

Life without chemicals would be inconceivable, but the potential risks and impacts to the environment associated with chemical production and chemical products are viewed critically. Eco-efficiency analysis considers the economic and life cycle environmental effects of a product or process, giving these equal weighting. The major elements of the environmental assessment include primary energy use, raw materials utilization, emissions to all media, toxicity, safety risk, and land use.

Sustainability science and engineering: the emergence of a new metadiscipline.

A case is made for growth of a new metadiscipline of sustainability science and engineering. This new field integrates industrial, social, and environmental processes in a global context. The skills required for this higher level discipline represent a metadisciplinary endeavor, combining information and insights across multiple disciplines and perspectives with the common goal of achieving a desired balance among economic, environmental, and societal objectives.

Development and evaluation of an environmental multimedia fate model CHEMGL for the Great Lakes region.

This paper describes the development of a multimedia compartmental model--CHEMGL--which predicts the fate and transport of chemicals in the Great Lakes region and can be used for risk assessment. CHEMGL includes 10 compartments that describe a given region: air boundary layer, free troposphere, lower stratosphere, surface water, sediment, surface soil, vadose soil, groundwater zone, plant foliage and plant root. The model assumes that the compartments are completely mixed and chemical equilibrium between the phases within each compartment is assumed (e.