Enzymatic Carboxylation of Resorcinol in Aqueous Triethanolamine at Elevated CO Pressure.

The fixation of CO by enzymatic carboxylation for production of valuable carboxylic acids is one way to recycle carbon. Unfortunately, this type of reaction is limited by an unfavourable thermodynamic equilibrium. An excess of the C1 substrate is required to increase conversions.

Online monitoring of phytate content in plant residuals during wet-treatment.

The occurrence of organically bound phosphorus (P) as phytate in plant-based feeding material is a challenge for livestock farming due to limited utilization during the digestion by the animal. Its excretion into the environment through the manure pathway, poses a challenge, due to increased eutrophication and restrictions for P. Hence, while the routine supplementation of phytase enzymes in monogastric diets is common practice, metabolically triggering endogenous plant enzymes by wet-treatment prior to feeding can also lead to a better utilization of phytate bound P and increased digestibility by the animal.

Electrochemical HO - stat mode as reaction concept to improve the process performance of an unspecific peroxygenase.

The electroenzymatic hydroxylation of 4-ethylbenzoic acid catalyzed by the recombinant unspecific peroxygenase from the fungus Agrocybe aegerita (rAaeUPO) was performed in a gas diffusion electrode (GDE)-based system. Enzyme stability and productivity are significantly affected by the way the co-substrate hydrogen peroxide (HO) is supplied. In this study, two in-situ electrogeneration modes of HO were established and compared.

Enzyme-Assisted Extraction of Ulvan from the Green Macroalgae .

Ulvan is a sulfated polysaccharide extracted from green macroalgae with unique structural and compositional properties. Due to its biocompatibility, biodegradability, and film-forming properties, as well as high stability, ulvan has shown promising potential as an ingredient of biopolymer films such as sustainable and readily biodegradable biomaterials that could replace petroleum-based plastics in diverse applications such as packaging. This work investigates the potential of as a source of ulvan.

Towards Sustainable Recycling of Epoxy-Based Polymers: Approaches and Challenges of Epoxy Biodegradation.

Epoxy resins are highly valued for their remarkable mechanical and chemical properties and are extensively used in various applications such as coatings, adhesives, and fiber-reinforced composites in lightweight construction. Composites are especially important for the development and implementation of sustainable technologies such as wind power, energy-efficient aircrafts, and electric cars. Despite their advantages, their non-biodegradability raises challenges for the recycling of polymer and composites in particular.

Bioleaching of valuable metals from spent LIBs followed by selective recovery of manganese using the precipitation method: Metabolite maximization and process optimization.

Despite the increased demand for resource recovery from spent lithium-ion batteries (LIBs), low Mn leaching efficiencies have hindered the development of this technology. A novel process was devised to enhance the dissolution of metals by producing citric acid using a molasses medium by Penicillium citrinum. This investigation used response surface methodology to investigate the influence of molasses concentration and media components on citric acid production, which demonstrated that molasses (18.

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid.

The importance of a compound that helps fight against influenza is, in times of a pandemic, self-evident. In order to produce these compounds in vast quantities, many researchers consider continuous flow reactors in chemical industry as next stepping stone for large scale production. For these reasons, the synthesis of -acetylneuraminic acid (Neu5Ac) in a continuous fixed-bed reactor by an immobilized epimerase and aldolase was investigated in detail.

Microbubble enhanced mass transfer efficiency of CO capture utilizing aqueous triethanolamine for enzymatic resorcinol carboxylation.

The present study focuses on the aeration of aqueous triethanolamine acting as reaction medium for biocatalytic carboxylations. For enhancing mass transfer in a bubble column reactor, microbubble aeration is applied and compared to conventional macrobubble aeration. Application of a 0.

Fatty alcohol synthesis from fatty acids at mild temperature by subsequent enzymatic esterification and metal-catalyzed hydrogenation.

Fatty alcohols are important products in chemical industry to be used in the formulation of surfactants and lubricants. This work describes a two step approach for the production of myristyl alcohol under neat conditions by combining a lipase catalyzed esterification of myristic acid and myristyl alcohol with a ruthenium catalyzed hydrogenation of the intermediate myristyl myristate. The esterification was carried out in a bubble column reactor with the commercial immobilized lipase B from Candida antarctica as a biocatalyst, while the hydrogenation was conducted under pressurized conditions being catalyzed by the homogeneous chemocatalyst Ru-Macho-BH.

FTIR based kinetic characterisation of an acid-catalysed esterification of 3-methylphthalic anhydride and 2-ethylhexanol.

In this study, an inline analytical method was designed and applied in process characterisation and development. The model reaction is the two-step diesterification of 3-methylphthalic anhydride with 2-ethylhexanol consisting of alcoholysis as the first step, followed by an acid-catalysed, second esterification step leading to the corresponding diester. The final product is a potential, alternative plasticiser.

Comparative investigation of fine bubble and macrobubble aeration on gas utility and biotransformation productivity.

The sufficient provision of oxygen is mandatory for enzymatic oxidations in aqueous solution, however, in process optimization this still is a bottleneck that cannot be overcome with the established methods of macrobubble aeration. Providing higher mass transfer performance through microbubble aerators, inefficient aeration can be overcome or improved. Investigating the mass transport performance in a model protein solution, the microbubble aeration results in higher k a values related to the applied airstream in comparison with macrobubble aeration.

Influence of oil, dispersant, and pressure on microbial communities from the Gulf of Mexico.

The Deepwater Horizon incident in the Gulf of Mexico in 2010 released an unprecedented amount of petroleum hydrocarbons 1500 meters below the sea surface. Few studies have considered the influence of hydrostatic pressure on bacterial community development and activity during such spills. The goal of this study was to investigate the response of indigenous sediment microbial communities to the combination of increased pressure, hydrocarbons and dispersant.

Influence of pressure and dispersant on oil biodegradation by a newly isolated Rhodococcus strain from deep-sea sediments of the gulf of Mexico.

A new Rhodococcus strain, capable of degrading crude oil, was isolated from the Gulf of Mexico deep-sea sediment and was investigated for its biodegradation characteristics under atmospheric as well as under deep-sea pressure (1500 m = 15 MPa). Additionally, the effect of dispersant (Corexit EC9500A) addition was studied. Rhodococcus sp.

Determination of trace amounts with ATR FTIR spectroscopy and chemometrics: 5-(hydroxymethyl)furfural in honey.

The feasibility of Attenuated Total Reflectance Fourier Transform Infrared (ATR FTIR) spectroscopy and chemometric modeling for analysis of trace compounds is studied on the example of 5-(hydroxymethyl)furfural (HMF) in honey up to a concentration of 110 ppm, and compared to results in literature. Randomized repeated measurements of the calibration samples were carried out to prevent analytical artifacts. A partial least squares (PLS) model was calculated for quantitative determination.

Deep Eutectic Solvents as Efficient Solvents in Biocatalysis.

'Ideal' solvents in biocatalysis have to fulfill a large number of requirements, such as high substrate solubility, high enzyme activity and stability, and positive effects on reaction equilibrium. In the past decades, many enzymatic synthesis routes in water-based and nonaqueous (organic solvents, ionic or supercritical fluids) reaction media have been developed. However, no solvent meets every demand for different reaction types at the same time, and there is still a need for novel solvents suited for different reaction types and applications.

Amine-Mediated Enzymatic Carboxylation of Phenols Using CO as Substrate Increases Equilibrium Conversions and Reaction Rates.

A variety of strategies is applied to alleviate thermodynamic and kinetic limitations in biocatalytic carboxylation of metabolites in vivo. A key feature to consider in enzymatic carboxylations is the nature of the cosubstrate: CO or its hydrated form, bicarbonate. The substrate binding and activation mechanism determine what the actual carboxylation agent is.

Investigation of a green process for the polymerization of catechin.

Flavonoids are polyphenolic secondary plant metabolites which possess antioxidant and anti-inflammatory properties. Besides, they have been shown to exhibit increased antioxidant properties in their polymerized form. Catechins are one of the attractive class of flavonoids which belong to the group of flavan-3-ols.

Improvement of the Process Stability of Arylmalonate Decarboxylase by Immobilization for Biocatalytic Profen Synthesis.

The enzyme arylmalonate decarboxylase (AMDase) enables the selective synthesis of enantiopure ()-arylpropinates in a simple single-step decarboxylation of dicarboxylic acid precursors. However, the poor enzyme stability with a half-life time of about 1.2 h under process conditions is a serious limitation of the productivity, which results in a need for high catalyst loads.

Biocatalytic Phosphorylations of Metabolites: Past, Present, and Future.

Phosphorus is a key element for life that occurs in living cells as a structural part of many key biochemicals. Phosphorus plays important functional roles in biocatalysis, such as making metabolic reaction steps irreversible by transferring energy-rich groups, using phosphate groups as leaving groups, or selectively hydrolyzing phosphorus-oxygen or phosphorus-nitrogen bonds. The large number of biocatalysts known to catalyze the transfer of phosphorus-containing groups from donor molecules to acceptor molecules covers a wide variety of reaction classes.

Kinetic insights into ϵ-caprolactone synthesis: Improvement of an enzymatic cascade reaction.

A computational approach for the simulation and prediction of a linear three-step enzymatic cascade for the synthesis of ϵ-caprolactone (ECL) coupling an alcohol dehydrogenase (ADH), a cyclohexanone monooxygenase (CHMO), and a lipase for the subsequent hydrolysis of ECL to 6-hydroxyhexanoic acid (6-HHA). A kinetic model was developed with an accuracy of prediction for a fed-batch mode of 37% for substrate cyclohexanol (CHL), 90% for ECL, and >99% for the final product 6-HHA. Due to a severe inhibition of the CHMO by CHL, a batch synthesis was shown to be less efficient than a fed-batch approach.

Bioreaction Engineering Leading to Efficient Synthesis of L-Glyceraldehyd-3-Phosphate.

Enantiopure L-glyceraldehyde-3-phosphate (L-GAP) is a useful building block in natural biological and synthetic processes. A biocatalytic process using glycerol kinase from Cellulomonas sp. (EC 2.

Evaluation of the Substrate Scope of Benzoic Acid (De)carboxylases According to Chemical and Biochemical Parameters.

The enzymatic carboxylation of phenolic compounds has been attracting increasing interest in recent years, owing to its regioselectivity and technical potential as a biocatalytic equivalent for the Kolbe-Schmitt reaction. Mechanistically the reaction was demonstrated to occur through electrophilic aromatic substitution/water elimination with bicarbonate as a cosubstrate. The effects of the substituents on the phenolic ring have not yet been elucidated in detail, but this would give detailed insight into the substrate-activity relationship and would provide predictability for the acceptance of future substrates.

Highly Effective Inhibition of Biofilm Formation by the First Metagenome-Derived AI-2 Quenching Enzyme.

Bacterial cell-cell communication (quorum sensing, QS) represents a fundamental process crucial for biofilm formation, pathogenicity, and virulence allowing coordinated, concerted actions of bacteria depending on their cell density. With the widespread appearance of antibiotic-resistance of biofilms, there is an increasing need for novel strategies to control harmful biofilms. One attractive and most likely effective approach is to target bacterial communication systems for novel drug design in biotechnological and medical applications.