scholarly journals Syngas Fermentation for the Production of Bio-Based Polymers: A Review

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3917
Author(s):  
Nirpesh Dhakal ◽  
Bishnu Acharya
Keyword(s):  
Downstream Processing ◽  
Product Inhibition ◽  
Syngas Fermentation ◽  
Multi Stage ◽  
Enzymatic Regulation ◽  
Synthetic Gas ◽  
Microbial Strains ◽  
Product Variation ◽  
Liquid Mass Transfer ◽  
Or Gene

Increasing environmental awareness among the general public and legislators has driven this modern era to seek alternatives to fossil-derived products such as fuel and plastics. Addressing environmental issues through bio-based products driven from microbial fermentation of synthetic gas (syngas) could be a future endeavor, as this could result in both fuel and plastic in the form of bioethanol and polyhydroxyalkanoates (PHA). Abundant availability in the form of cellulosic, lignocellulosic, and other organic and inorganic wastes presents syngas catalysis as an interesting topic for commercialization. Fascination with syngas fermentation is trending, as it addresses the limitations of conventional technologies like direct biochemical conversion and Fischer–Tropsch’s method for the utilization of lignocellulosic biomass. A plethora of microbial strains is available for syngas fermentation and PHA production, which could be exploited either in an axenic form or in a mixed culture. These microbes constitute diverse biochemical pathways supported by the activity of hydrogenase and carbon monoxide dehydrogenase (CODH), thus resulting in product diversity. There are always possibilities of enzymatic regulation and/or gene tailoring to enhance the process’s effectiveness. PHA productivity drags the techno-economical perspective of syngas fermentation, and this is further influenced by syngas impurities, gas–liquid mass transfer (GLMT), substrate or product inhibition, downstream processing, etc. Product variation and valorization could improve the economical perspective and positively impact commercial sustainability. Moreover, choices of single-stage or multi-stage fermentation processes upon product specification followed by microbial selection could be perceptively optimized.

Downstream processing of virus-like particles: Single-stage and multi-stage aqueous two-phase extraction

2015 ◽  
Vol 1383 ◽  
pp. 35-46 ◽  
Author(s):  
Christopher Ladd Effio ◽  
Lukas Wenger ◽  
Ozan Ötes ◽  
Stefan A. Oelmeier ◽  
Richard Kneusel ◽  
...  
Keyword(s):  
Downstream Processing ◽  
Single Stage ◽  
Phase Extraction ◽  
Two Phase ◽  
Virus Like Particles ◽  
Multi Stage ◽  
Aqueous Two Phase Extraction

scholarly journals Tailoring Celluclast® Cocktail’s Performance towards the Production of Prebiotic Cello-Oligosaccharides from Waste Forest Biomass

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 897 ◽  
Author(s):  
Anthi Karnaouri ◽  
Leonidas Matsakas ◽  
Saskja Bühler ◽  
Madhu Nair Muraleedharan ◽  
Paul Christakopoulos ◽  
...  
Keyword(s):  
Forest Biomass ◽  
Hydrolysis Product ◽  
Enzyme Reaction ◽  
Downstream Processing ◽  
Sustainable Production ◽  
Fine Tuning ◽  
Forest Residues ◽  
Multi Stage ◽  
Glucose Ratio ◽  
Probiotic Strains

The main objective of this study focused on the sustainable production of cellobiose and other cellulose-derived oligosaccharides from non-edible sources, more specifically, from forest residues. For this purpose, a fine-tuning of the performance of the commercially available enzyme mixture Celluclast® was conducted towards the optimization of cellobiose production. By enzyme reaction engineering (pH, multi-stage hydrolysis with buffer exchange, addition of β-glucosidase inhibitor), a cellobiose-rich product with a high cellobiose to glucose ratio (37.4) was achieved by utilizing organosolv-pretreated birch biomass. In this way, controlled enzymatic hydrolysis combined with efficient downstream processing, including product recovery and purification through ultrafiltration and nanofiltration, can potentially support the sustainable production of food-grade oligosaccharides from forest biomass. The potential of the hydrolysis product to support the growth of two Lactobacilli probiotic strains as a sole carbon source was also demonstrated.

scholarly journals Bio-produced Propionic Acid: A Review

2017 ◽  
Vol 62 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Aladár Vidra ◽  
Áron Németh
Keyword(s):  
Propionic Acid ◽  
Strain Improvement ◽  
Product Yield ◽  
Downstream Processing ◽  
Product Inhibition ◽  
Product Recovery ◽  
Acid Fermentation ◽  
Fermentation Processes ◽  
Propionic Acid Production ◽  
Downstream Area

Propionic acid is a platform chemical, antifungal agent and important chemical intermediate. Current industrial production of propionic acid is mainly through petrochemical processes because the conventional method of the propionic acid fermentation is uneconomical due to low product yield, productivity and product concentration caused by end-product inhibition. The coproduction of acetic and succinic acids in the propionic acid fermentation processes also makes downstream processing more complicated and costly. To the best of our knowledge there are several and recent reviews in the available literature on propionic acid fermentation processes and strain improvement techniques, but only a few on product recovery and purification, i.e. downstreaming. However, to realize a biorefinery, where propionic acid is a key intermediate, complex discussion of up-, and downstreaming is required. Therefore in this review a short overview of the whole bio-based propionic acid production process is presented including recent results of both upstream and downstream area. Thus the biosynthetic pathways, the significant results of native and recombinant producer strains as well as product recovery are discussed.

Enhancing Downstream Processing of Biologics or Gene Therapies

2019 ◽  
Vol 39 (4) ◽  
pp. 55-57
Author(s):  
Vinit Saxena ◽  
Salah Ahmed ◽  
Naveen Kumar Singh
Keyword(s):  
Downstream Processing ◽  
Gene Therapies ◽  
Or Gene

scholarly journals FAST-forge of Titanium Alloy Swarf: A Solid-State Closed-Loop Recycling Approach for Aerospace Machining Waste

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 296 ◽  
Author(s):  
Nicholas S. Weston ◽  
Martin Jackson
Keyword(s):  
Titanium Alloy ◽  
Solid State ◽  
Closed Loop ◽  
Hot Forging ◽  
Weight Ratio ◽  
High Strength ◽  
Downstream Processing ◽  
Processing Route ◽  
Aerospace Applications ◽  
Multi Stage

Titanium alloys have excellent properties, but components are very expensive due to the high levels of processing required, such as vacuum melting, multi-stage forging, and machining. As a result, forged titanium alloy components are largely exclusive to the aerospace industry, where a high strength-to-weight ratio, corrosion resistance, and excellent fatigue resistance are essential. However, a typical buy-to-fly ratio for such components is approximately 9:1, as much of the forged billet is machined to swarf. The quantity of waste titanium alloy swarf generated is increasing as aircraft orders, and the titanium components contained within them, are increasing. In this paper, waste swarf material has been recycled using the two-step solid-state FAST-forge process, which utilizes field assisted sintering technology (FAST) followed by hot forging. Cleaned Ti-6Al-4V swarf was fully consolidated using the FAST process at sub-transus and super-transus temperatures, followed by hot forging at sub-transus temperatures at different strain rates. It was demonstrated that swarf-derived Ti-6Al-4V FAST billets have equivalent hot forging flow behaviour and resultant microstructures when directly compared to equivalently processed conventional expensive hydride–dehydride powder, and previously reported Kroll-derived melt-wrought material. This demonstrates that titanium swarf is a good quality feedstock for downstream processing. Additionally, FAST-forge is a viable processing route for the closed-loop recycling of machining waste for next-generation components in vehicles and non-aerospace applications, which is game changing for the economics of titanium alloy components.

scholarly journals Integrating Syngas Fermentation into a Single-Cell Microbial Electrosynthesis (MES) Reactor

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Vasan Sivalingam ◽  
Vafa Ahmadi ◽  
Omodara Babafemi ◽  
Carlos Dinamarca
Keyword(s):  
Mass Transfer ◽  
Acetic Acid ◽  
Single Cell ◽  
Second Phase ◽  
Syngas Fermentation ◽  
Mixed Culture Fermentation ◽  
Microbial Electrosynthesis ◽  
Liquid Mass ◽  
Gas Fermentation ◽  
Liquid Mass Transfer

This study presents a series of experiments to test the integration of syngas fermentation into a single-cell microbial electrosynthesis (MES) process. Minimal gas–liquid mass transfer is the primary bottleneck in such gas-fermentation processes. Therefore, we hypothesized that MES integration could trigger the thermodynamic barrier, resulting in higher gas–liquid mass transfer and product-formation rates. The study was performed in three different phases as batch experiments. The first phase dealt with mixed-culture fermentation at 1 bar H2 headspace pressure. During the second phase, surface electrodes were integrated into the fermentation medium, and investigations were performed in open-circuit mode. In the third phase, the electrodes were poised with a voltage, and the second phase was extended in closed-circuit mode. Phase 2 demonstrated three times the gas consumption (1021 mmol) and 63% more production of acetic acid (60 mmol/L) than Phase 1. However, Phase 3 failed; at –0.8 V, acetic acid was oxidized to yield hydrogen gas in the headspace.

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