Advances in the green chemistry of coordination polymer materials

Streamlining Design, Engineering, and Applications of Enzymes for Sustainable Biocatalysis

/pdf/production-of-levulinic-acid-and-alkyl-levulinates-a-process-mhwbrcuw.pdf

Production of levulinic acid and alkyl levulinates: a process insight

5-Hydroxymethylfurfural (HMF) has emerged as a crucial bio-based chemical building block in the drive towards developing materials from renewable resources, due to its direct preparation from sugars and its readily diversifiable scaffold. A key obstacle in transitioning to bio-based plastic production lies in meeting the necessary industrial production efficiency, particularly in the cost-effective conversion of HMF to valuable intermediates. Toward addressing the challenge of developing scalable technology for oxidizing crude HMF to more valuable chemicals, here we report coordinated reaction and enzyme engineering to provide a galactose oxidase (GOase) variant with remarkably high activity toward HMF, improved O2 binding and excellent productivity (>1,000,000 TTN). The biocatalyst and reaction conditions presented here for GOase catalysed selective oxidation of HMF to 2,5-diformylfuran offers a productive blueprint for further development, giving hope for the creation of a biocatalytic route to scalable production of furan-based chemical building blocks from sustainable feedstocks.

/pdf/toward-scalable-biocatalytic-conversion-of-5-qri3qu5feh.pdf

Toward scalable biocatalytic conversion of 5-hydroxymethylfurfural by galactose oxidase using coordinated reaction and enzyme engineering

Background A wide range of conventional and non-conventional technologies have been employed to extract a wide range of bioactive compounds from the complex matrices of seaweeds. Green extraction technologies are increasingly employed to improve extraction efficiencies. Scope and approach The objective of this review was to outline various approaches employed for the extraction of bioactives from seaweeds. This review covers various pretreatment methods generally employed prior to extraction, and their combinations with conventional and green extraction technologies. Novel technologies which can be employed with or without pretreatments to improve existing processes are also discussed. Key findings The role of pretreatments is of utmost importance and have significant impacts on the quality and quantity of target compounds. Combinations of different cell disruption technologies and extraction methods can enhance the extractability of compounds with higher purity and contribute towards improved process efficiency.

Advances in pre-treatment techniques and green extraction technologies for bioactives from seaweeds

2,5-Furandicarboxylic acid (FDCA) is one of the top biomass-derived value-added chemicals. It can be produced from fructose and other C6 sugars via formation of 5-hydroxymethilfurfural (HMF) intermediate. Most of the chemical methods for FDCA production require harsh conditions, thus as an environmentally friendly alternative, an enzymatic conversion process can be applied. Commercially available horseradish peroxidase (HRP) and lignin peroxidase (LPO), alcohol (AO) and galactose oxidase (GO), catalase (CAT) and laccase (LAC) were tested against HMF, 2,5-diformylfuran (DFF), 5-hydroxymethyl-2-furoic acid (HMFA) and 5-formyl-2-furoic acid (FFA). Enzyme concentrations were determined based on the number of available active sites and reactions performed at atmospheric oxygen pressure. AO, GO, HRP and LPO were active against HMF, where LPO and HRP produced 0.6 and 0.7% of HMFA, and GO and AO produced 25.5 and 5.1% DFF, respectively. Most of the enzymes had only mild (3.2% yield or less) or no activity against DFF, HMFA and FFA, with only AO having a slightly higher activity against FFA with an FDCA yield of 11.6%. An effect of substrate concentration was measured only for AO, where 20 mM HMF resulted in 19.5% DFF and 5 mM HMF in 39.9% DFF, with a Km value of 14 mM. Some multi-enzyme reactions were also tested and the combination of AO and CAT proved most effective in converting over 97% HMF to DFF in 72 h. Our study aimed at understanding the mechanism of conversion of bio-based HMF to FDCA by different selected enzymes. By understanding the reaction pathway, as well as substrate specificity and the effect of substrate concentration, we would be able to better optimize this process and obtain the best product yields in the future.

/pdf/enzymatic-conversion-reactions-of-5-hydroxymethylfurfural-4tyhgtzmgl.pdf

Enzymatic conversion reactions of 5-hydroxymethylfurfural (HMF) to bio-based 2,5-diformylfuran (DFF) and 2,5-furandicarboxylic acid (FDCA) with air: mechanisms, pathways and synthesis selectivity

Enzymatic bioconversion process of lignin: mechanisms, reactions and kinetics.

Alginate is the dominant structural polysaccharide found in brown seaweed. The industrial process systems for alginic acid isolation use formalin to insolubilize unwanted molecules like polyphenols so they do not get extracted along with the desired polysaccharide. In our present study, we tested six formalin alternatives that would not only allow us to isolate alginate but also retrieve the polyphenol-rich fraction which has uses in the food, cosmetic, and pharmaceutical industries. Sodium alginate was isolated from the marine macroalgae species Laminaria hyperborea with the aid of a common 0.2 wt% formalin solution and compared against water and polar organic fluids, i.e., pure- or a 50 wt% aqueous phase mixture of methanol, ethanol, or acetone. Beside solute molecular dissolution, several commercial mechanical pre-treatment steps were successfully tested, which showed a positive effect correlation with the yield of the produced alginate-rich fraction. Identification of alginate in the samples was confirmed using FT-IR analysis, where some possible impurities were indicated. Evaluated methodologies mostly contributed to higher biopolymer fractions, which were obtained. Furthermore, it was possible to extract up to 128 mg GAE (100 g)−1 of dry weight of polyphenol-rich fraction in resource side streams, impacting the valorization of feedstock.

Cascade valorization process of brown alga seaweed Laminaria hyperborea by isolation of polyphenols and alginate

Mechanistic kinetic modelling of enzyme-catalysed oxidation reactions of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA)

Extended Abstract 2,5-Furandicarboxylic acid (FDCA) is one of the top biomass-derived value-added chemicals. It can be produced from fructose and other sugars via formation of 5-hydroxymethilfurfural (HMF) intermediate [1]. FDCA and its derivates can be used in many fields, but the most promising application is the replacement of oil-derived tetraphtalate in the synthesis of polyethylene tetraphthalate (PET) plastics [2]. The oxidation of HMF to FDCA can proceed via two routes: (1) oxidation of the aldehyde group to form 5-hydroxymethyl-2-furoic acid (HMFA) which is then oxidized to 5-formyl-2-furoic acid (FFA) and FDCA, and (2) oxidation of the alcohol group to form 2,5-diformylfuran (DFF), followed by further oxidations to FFA and FDCA. Most of the chemical methods for FDCA production require harsh conditions, like high pressure and temperature, organic solvents and special salts, making the process environmentally unfriendly and high cost [3]. As an environmentally friendly alternative an enzymatic conversion process can be applied [4]. However, to our knowledge, only a few enzymes have been found to be active toward HMF and most of them were not able to oxidize HMF to FDCA. Thus, to achieve a full conversion with high FDCA yields, a combination of multiple enzymes is needed [5]–[7]. In order to better understand the catalytic activity of some of these enzymes we broke the oxidation of HMF to FDCA down to separate reactions to determine all the possible substrates as well as reaction products for each individual enzyme. Based on this data we then tested different combinations of enzymes in a simple one-pot reaction to determine which one gives the best results. The enzymes used in our work were commercially available horseradish peroxidase (HRP), a fungal alcohol (AO) and galactose oxidase (GO), catalase (Cat), laccase (Lac) and a lignin peroxidase (LPO) and their activity was tested against HMF, DFF, HMFA and FFA. AO, GO, HRP and LPO were active against HMF, with AO and GO producing DFF and HRP and LPO producing HMFA. All enzymes were only mildly active against DFF forming FFA and some HMF. GO, Lac, LPO and HRP were active against HMFA producing FFA and FDCA. All enzymes were also active against FFA. However, product yields obtained with these single-enzyme reactions were mostly low, the highest being 11%. The exception was conversion of FFA to FDCA where some of the yields were above 80%. We then prepared simple multi-enzyme reactions with HMF: AO or GO with Cat or with Cat and HRP. Combining AO and Cat notably increased the yield of DFF but decreased the yield of FFA. In the case of GO and Cat the yield of DFF also increased but to a smaller degree and with no formation of FFA. Adding HRP to each mixture increased the yield of FFA and DFF in the case of GO, but decreased the yield of DFF in the case of AO. To increase the yields further as well as obtain the final product FDCA, more enzyme combinations will have to be tested and possibly, some new enzymes considered.

/pdf/enzymatic-production-process-of-bio-based-2-5-3yvjsbah0q.pdf

Miša Mojca Cajnko

Papers

Enzymatic conversion reactions of 5-hydroxymethylfurfural (HMF) to bio-based 2,5-diformylfuran (DFF) and 2,5-furandicarboxylic acid (FDCA) with air: mechanisms, pathways and synthesis selectivity

Enzymatic bioconversion process of lignin: mechanisms, reactions and kinetics.

Cascade valorization process of brown alga seaweed Laminaria hyperborea by isolation of polyphenols and alginate

Mechanistic kinetic modelling of enzyme-catalysed oxidation reactions of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA)

Enzymatic Production Process of Bio-based 2,5-Furandicarboxylic Acid (FDCA) from 5-Hydrohymethilfurfural (HMF)