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The present invention is in the field of a process for producing an ester, such as a biobased ester, from an aqueous biomass comprising solution, batch wise or continuously, wherein use of raw material is limited and if possible re-used. The present invention is in the field of green technology., BT/Biotechnology, Applied Sciences

Biotechnology, Applied Sciences

Isobutene (2-methylpropene) is one of those chemicals for which bio-based production might replace the petrochemical production in the future. Currently, more than 10 million metric tons of isobutene are produced on a yearly basis. Even though bio-based production might also be achieved through chemocatalytic or thermochemical methods, this review focuses on fermentative routes from sugars. Although biological isobutene formation is known since the 1970s, extensive metabolic engineering is required to achieve economically viable yields and productivities. Two recent metabolic engineering developments may enable anaerobic production close to the theoretical stoichiometry of 1isobutene + 2CO2 + 2H2O per mol of glucose. One relies on the conversion of 3-hydroxyisovalerate to isobutene as a side activity of mevalonate diphosphate decarboxylase and the other on isobutanol dehydration as a side activity of engineered oleate hydratase. The latter resembles the fermentative production of isobutanol followed by isobutanol recovery and chemocatalytic dehydration. The advantage of a completely biological route is that not isobutanol, but instead gaseous isobutene is recovered from the fermenter together with CO2. The low aqueous solubility of isobutene might also minimize product toxicity to the microorganisms. Although developments are at their infancy, the potential of a large scale fermentative isobutene production process is assessed. The production costs estimate is 0.9 € kg?1, which is reasonably competitive. About 70% of the production costs will be due to the costs of lignocellulose hydrolysate, which seems to be a preferred feedstock., BT/Biotechnology, Applied Sciences

Irreversible reactions are being applied in enzymatic kinetic resolution to obtain enantiomerically pure compounds from racemic mixtures. Using model calculations for situations without mass transfer limitation, we show that reversible reactions might also be useful for enzymatic kinetic resolution, provided that countercurrent systems are used rather than batch or cocurrent systems. The required reaction time or enzyme amount in a countercurrent system is much lower than in an analogous cocurrent system or its batch equivalent. More importantly, often the calculated yield and enantiomeric excess are better in countercurrent systems. Racemization can also be favorably used in countercurrent systems. Consequently, to achieve with a reversible reaction a particular enantiomeric excess and yield, a countercurrent system needs less dilution or activated co-reactant and less enantioselective enzyme than a cocurrent system., BT/Biotechnology, Applied Sciences

A bifunctional hydratase/alcohol dehydrogenase was isolated from the cyclohexanol degrading bacterium Alicycliphilus denitrificans DSMZ 14773. The enzyme catalyzes the addition of water to ?,?-unsaturated carbonyl compounds and the subsequent alcohol oxidation. The purified enzyme showed three subunits in SDS gel, and the gene sequence revealed that this enzyme belongs to the molybdopterin binding oxidoreductase family containing molybdopterins, FAD, and iron-sulfur clusters., BT/Biotechnology, Applied Sciences

The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilized biocatalysts for the enzymatic hydrolysis of penicillin G (PenG). The monolithic biocatalyst was tested in a monolith loop reactor (MLR) and compared with conventional reactor systems using free PGA, and a commercially available immobilized PGA. The optimal immobilization protocol was found to be 5 g l-1 PGA, 1% chitosan, 1.1% glutaraldehyde and pH 7. Final PGA loading on glass plates was 29 mg ml-1 gel. For 400 cpsi monoliths, the final PGA loading on functionalized monoliths was 36 mg ml-1 gel. The observed volumetric reaction rate in the MLR was 0.79 mol s-1 m-3 monolith. Apart from an initial drop in activity due to wash out of PGA at higher ionic strength, no decrease in activity was observed after five subsequent activity test runs. The storage stability of the biocatalysts is at least a month without loss of activity. Although the monolithic biocatalyst as used in the MLR is still outperformed by the current industrial catalyst (immobilized preparation of PGA, 4.5 mol s-1 m-3 catalyst), the rate per gel volume is slightly higher for monolithic catalysts. Good activity and improved mechanical strength make the monolithic bioreactor an interesting alternative that deserves further investigation for this application. Although moderate internal diffusion limitations have been observed inside the gel beads and in the gel layer on the monolith channel, this is not the main reason for the large differences in reactor performance that were observed. The pH drop over the reactor as a result of the chosen method for pH control results in a decreased performance of both the MLR and the packed bed reactor compared to the batch system. A different reactor configuration includ, DelftChemTech, Applied Sciences

The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations., Biotechnology, Applied Sciences

The primary aim of this study is to investigate and analyze the sugar-ethanol plants operating in Brazil to construct a raw model to gain better understanding and insight about the technical and economical aspects of the currently operating plants. And, the secondary aim is to combine the knowledge gathered from the currently existing plant with the future design idea of converting lignocellulose into ethanol together with sucrose. The major products of the plants are ethanol and sugar. The proposed plant capacity is 5 million metric tones of sugar cane per year. The plant operation time is 174 days (4176 h) during the harvest season. The plant location is Sao Paulo state of Brazil. The designed 2005 plant produces 99.88% anhydrous ethanol and white sugar with 165,956 and 379,401 ton yearly capacities respectively. The plant is self sufficient in terms of steam and electricity requirements. The results of economical analysis of the 2005 plant reveal that the required total capital investment is $102 million. The investment is determined using the location factor of 0.4 for Brazil. The net present value of the investment is $166 million using discount rate of 4%. The same analysis reveals that the maximum interest rate that investment can remain economical through out the investment period is 26.5%. The sensitivity analysis showed that the economical values are highly sensitive to sugar cane, ethanol and sugar prices. The designed 2015 plant produces 99.89% anhydrous ethanol and white sugar with 396,872 and 370,405 ton yearly capacities respectively. For the future plant the microorganisms for fermentation are selected as recombinant Sacharomyces cerevisiae that can metabolize pentose and hexose sugars. the pretreatment method for the lignocellulose breakdown is selected as acid catalyzed steam explosion. The cellulose is hydrolyzed using cellulase enzyme. The plant is self sufficient in steam production, however, some portion of electricity demand is required to be, Applied Sciences

The invention relates to a method of preparing a reaction product such as a primary amide, by means of two reagents A and B, which reagents form a salt that impedes fast conversion. The concentrations of the reagent A and the reagent B are chosen such that they comply with formula (I) wherein [A]T represents the concentration of the first reagent A in relation to the total volume taken up by the reagents A, B, and the solvent., Applied Sciences