Downstream Processing Options Research Articles

Bioplastic Production from Agri-Food Waste through the Use of Haloferax mediterranei: A Comprehensive Initial Overview.

The research on bioplastics (both biobased and biodegradable) is steadily growing and discovering environmentally friendly substitutes for conventional plastic. This review highlights the significance of bioplastics, analyzing, for the first time, the state of the art concerning the use of agri-food waste as an alternative substrate for biopolymer generation using Haloferax mediterranei. H. mediterranei is a highly researched strain able to produce polyhydroxybutyrate (PHB) since it can grow and produce bioplastic in high-salinity environments without requiring sterilization. Extensive research has been conducted on the genes and pathways responsible for PHB production using H. mediterranei to find out how fermentation parameters can be regulated to enhance cell growth and increase PHB accumulation. This review focuses on the current advancements in utilizing food waste as a substitute for costly substrates to reduce feedstock expenses. Specifically, it examines the production of biomass and the recovery of PHB from agri-food waste. Furthermore, it emphasizes the characterization of PHB and the significance of hydroxyvalerate (HV) abundance in the formation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymer. The downstream processing options are described, and the crucial factors associated with industrial scale-up are assessed, including substrates, bioreactors, process parameters, and bioplastic extraction and purification. Additionally, the economic implications of various options are discussed.

Techno-economic Feasibility of Thermochemical Conversion Pathways for Regional Agricultural Waste Biomass

This study examines four prominent thermochemical conversion technologies such as slow pyrolysis (SP), fast pyrolysis (FP), gasification (GA) and hydrothermal liquefaction (HTL), for treating poultry litter in New York State (NYS). Nine cases involving various combinations of the four technologies and different downstream processing options such as bio-oil upgrading, Fischer-Tropsch conversion and combined heat and power generation are chosen based on the product composition and distribution. High-fidelity process simulations for each technological platform are performed to derive the mass and energy balance information. Calculations and breakdown of the equipment costs, capital costs, operating and maintenance costs and utilities are provided and compared extensively for each of the nine cases. The economic performance is further analyzed by calculating and comparing the resultant net present values (NPV), ranging from $10 M to $170 M (SP), $89 M to $314.5 M (FP), $28 M to $196 M (HTL) and $25 M to $234 M (GA). The greenhouse gas emission inventories are also compiled to understand the corresponding impacts of different downstream processing choices (ranging from 217 to 494.5 kg CO2-eq/t feedstock with both the pyrolysis technologies outperforming the others in most cases) and to highlight the trade-off with economic performance. Through sensitivity analysis, the influential factors requiring further investigation are identified and it is found that plant capacity and bio-oil yield are the most important parameters for the fast pyrolysis systems, biochar price for SP is the single most important parameter.

Techno-Economic Feasibility and Spatial Analysis of Thermochemical Conversion Pathways for Regional Poultry Waste Valorization

This study examines prominent thermochemical conversion technologies, such as slow pyrolysis, fast pyrolysis, gasification, and hydrothermal liquefaction, for treating poultry litter in New York State (NYS). Nine cases involving combinations of the four technologies and different downstream processing options such as bio-oil upgrading and Fischer–Tropsch conversion are chosen based on the product distribution. High-fidelity process simulations are performed to derive the mass and energy balance. Economic performance for the nine cases varied widely with largely overlapping net present values, ranging from $10MM to $170MM (slow pyrolysis), $89MM to $314.5MM (fast pyrolysis), $28MM to $196MM (hydrothermal liquefaction), and $25MM to $234MM (gasification). Both pyrolysis technologies had 18% to 56% lower greenhouse gas (GHG) emissions than the other technologies. GHG balances showed trade-offs with economic performance. Sensitivity analysis identified carbon credits, products’ market price, and plant capacity as the most influential factors. Building one centralized biorefinery in NYS especially for fast pyrolysis was more economically feasible than building multiple smaller biorefineries (biochar breakeven price of −$128 to −$91/ton vs $74 to $93/ton). The trend for slow pyrolysis was similar but with comparatively little difference (biochar breakeven price of $59 to $96/ton for one biorefinery vs $76 to $91/ton for multiple biorefineries).

Scale-up of electrospinning technology: Applications in the pharmaceutical industry.

Recently, electrospinning (ES) of fibers has been shown to be an attractive strategy for drug delivery. One of the main features of ES is that a wide variety of drugs can be loaded into the fibers to improve their bioavailability, to enhance dissolution, or to achieve controlled release. Besides, ES is a continuous technology with low energy consumption, which can make it a very economic production alternative to the widely used freeze drying and spray drying. However, the low production rate of laboratory-scaled ES has limited the industrial application of the technology so far. This article covers the various ES technologies developed for scaled-up fiber production with an emphasis on pharmaceutically relevant examples. The methods used for increasing the productivity are complied, which is followed by a review of specific examples from literature where these technologies are utilized to produce oral drug delivery systems. The different technologies are compared in terms of their basic principles, advantages, and limitations. Finally, the different downstream processing options to prepare tablets or capsules containing the electrospun drug are covered as well. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

DECA, A Comprehensive, Automatic Post-processing Program for HDX-MS Data*

Amide hydrogen-deuterium exchange mass spectrometry (HDX-MS) has become widely popular for mapping protein-ligand interfaces, for understanding protein-protein interactions, and for discovering dynamic allostery. Several platforms are now available which provide large data sets of amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) data. Although many of these platforms provide some down-stream processing, a comprehensive software that provides the most commonly used down-stream processing tools such as automatic back-exchange correction options, analysis of overlapping peptides, calculations of relative deuterium uptake into regions of the protein after such corrections, rigorous statistical analysis of the significance of uptake differences, and generation of high quality figures for data presentation is not yet available. Here we describe the Deuterium Exchange Correction and Analysis (DECA) software package, which provides all these downstream processing options for data from the most popular mass spectrometry platforms. The major functions of the software are demonstrated on sample data.

Towards bacterial lipopeptide products for specific applications — a review of appropriate downstream processing schemes

Abstract Lipopeptides are versatile molecules that are viable and potential replacements for synthetic surfactants in agricultural, pharmaceutical, food and cosmetic industries. While process optimization and intensification approaches have significantly improved lipopeptide production in terms of yield and productivity, downstream processing options to produce tailor-made lipopeptide products of different degrees of purity for specific applications have received considerably less attention. The use of conventional downstream methods such as solvent extraction, membrane filtration, adsorption and size exclusion has satisfactorily addressed the demand of lipopeptide mixtures to some extent, but the lack of well-established downstream techniques for these molecules still withholds their complete commercial realization. Moreover, fractionation of lipopeptide mixtures into families or individual isoforms is undeveloped, significantly limiting the use of lipopeptides for high end applications. This review highlights the recent developments in downstream processing of lipopeptides and discusses their pertinence on a case-to case basis in obtaining lipopeptides of appropriate purity for distinct and diverse applications.

Pulsed Electric Field Treatment of Microalgae—Benefits for Microalgae Biomass Processing

In this paper, we demonstrate how pulsed electric field (PEF) treatment of microalgae biomass opens promising downstream processing options for an energetic use of algae. The fact that lipid droplets remain intracellular after treatment facilitates selective processing. After separation of the water-soluble cell contents, the algae lipids can be extracted with adequate solvents. The use of the environmental-friendly solvent ethanol results in an extraction yield from wet and dry biomass that, on average, is four times higher compared with untreated samples. Especially, the use of wet biomass opens a promising processing route for an energetic use of microalgae, because the energy consumed conventionally for drying of the biomass is considerably higher than the energy required for PEF treatment, i.e., ~ 1.5 MJ/kg of dry biomass.

Effect of post-precipitation conditions on surface properties of colloidal metal sulphide precipitates

Metal sulphide precipitation is important in several hydrometallurgical processes. However, challenges exist in solid–liquid separation and recovery of the colloidal precipitates produced in some systems. This study presents the effect of downstream processing options on the surface properties of colloidal particles produced during copper and zinc sulphide precipitation. XRD and EDAX characterisation indicated the copper precipitate was a mixture of covellite (63%) and copper hydroxysulphate (37%), while the zinc sulphide was more pure, but less crystalline. The effect on surface charge and aggregation tendency of different concentrations of background electrolyte (1–100mM KCl), suspension pH, aqueous sulphide, a divalent (Ca2+) and trivalent (Al3+) cation were studied. The magnitude of the negative surface charge increased with increasing suspension pH (pH 6 to pH 11) for both copper and zinc precipitates. The addition of aqueous sulphide (0.84mM) to the zinc precipitate resulted in a significant decrease in the zeta potential and suppressed aggregation, due to adsorption of the negatively charged sulphide ions. This effect was reduced at high ionic strength. A higher sulphide concentration was required to replicate the phenomenon with the copper precipitate due to sulphidisation of the copper hydroxysulphate initially. Addition of a divalent cation (Ca2+) to the suspension had little effect on the surface charge of the particles and did not promote aggregation. However, addition of a small amount (0.5mM) of Al3+ ions resulted in a significant change in surface charge (−30 to −10mV for copper and −23mV to −5mV for zinc) and subsequent aggregation. The results of this study show that downstream processing of colloidal metal sulphide precipitates, produced where supersaturation cannot be managed, can lead to effective solid–liquid separation, by changing the surface properties of the precipitate.

Hydrothermal Treatment (HTT) of Microalgae: Detailed Molecular Characterization of HTT Oil in View of HTT Mechanism Elucidation

The understanding of the chemical nature of the oil is important for both the optimization of the process and the design of upgrading strategies for further use as an energy carrier or toward transportation fuels. Hydrothermal treatment (HTT) oil is a complex matrix, whose composition is strongly affected by the feedstock type and by the HTT experimental conditions. In the present work, HTT oil from Desmodesmus sp. was subjected to a detailed chemical analysis. Various characterization techniques (silica gel chromatography, methanolysis, size exclusion chromatography, analytical pyrolysis, elemental analysis, and thermogravimetric techniques) were coupled to gather clearer information on the chemical nature of HTT oil obtained at different reaction times, temperatures, and slurry concentrations. Special attention was paid to the fate of N in the HTT process and the nature of the N-containing species in the oil. By cross-checking results from the chemical characterization of the oil with process data, it was finally possible to identify some different competitive reactions involved in the formation of HTT oil at different conditions. Results show that main compounds obtained at low temperature are still classifiable as lipids, which are extractable without the HTT, together with some short chain algaenan and some hydrophobic protein fragments that end up in the organic solvent phase. At higher temperature (300–375 °C), proteins and cellulose started to break down, giving cyclic dipeptides and amino acids side chains (by pyrolysis-like reactions), carbohydrates derivatives (e.g., furans) and products from the cross reaction of proteins and carbohydrates (e.g., formation of alkyl-pyrrolidinones, pyrazines, pyrroles and melanoidin-like materials). This phenomenon is responsible for the observed increase in oil mass yield with increasing processing temperature, as well as the increase in nitrogen content of the oil. Optimization of the production of fuels and fuel precursors by HTT should be done in conjunction with evaluation of downstream processing options and/or the possibility to recycle unconverted material to the algae cultivation.

Recovering precious metals from electronic scrap

This article characterizes electronic scrap in terms of origin and composition and describes the steps in preliminary processing: sorting, calcination, combustion, shredding, and sampling. Hydrometallurgical and pyrometallurgical process technologies for the concentration and recovery of precious-metals values in scrap are reviewed, and some downstream processing options are outlined. The article concludes with some caveats concerning the risky but potentially profitable business of recovery of precious metals from electronic scrap.