Haute couture: molecules and biocatalysts

For the next 50 years, chemistry will be just as fashionable as it has been in the past 50 years. In fact, the role of chemistry is bigger than ever with the help of bioinformatics that are riding the waves of genomic revolution. Bio-based processes and entities are becoming more organic with civilians requesting sustainable approaches to everything. Globally, the runway for the implementation of industrial biotechnology is nearly complete and is ready to overtake harsh chemical processes. However, major issues such as the high capital costs of advanced biocatalysts, organic solvent replacements and bioreactor technologies are the winding roads to progress. Research on enzymes and liquid engineering has brought us to new dimensions of understanding the unknown capabilities of unnatural enzyme systems at the molecular and atomic levels. The development of designer biocatalysts for industrial purposes to substitute traditional processes is gaining interest. Utilisation of local microbial enzymes and our tropical biodiversity for the discovery and identification of new biocatalysts through advanced structural and synthetic biology are the key focuses. In addition, bioinformatics or the in silico approach of designing novel single molecules to macromolecules is a powerful tool to model any mechanism and structure. By all accounts, the efficient use of bio-renewable resources requires blending different systems of chemistry and biology; heterogeneous and homogeneous, enzymes and metals, microbial and yeast, etc. This technology presents current and potential areas in which the use of a biocatalyst is a prerequisite for an economical application in green organic syntheses. Considering the industrial importance of the platform and fine chemicals, the optimal conditions for up scaling the process are evaluated by statistical methods while taking into consideration, all of the sustainable, environmental and economical evaluations. It will be essential for chemists or biological engineers to design and model the biocatalysts to significantly guide and quicken the steps for synthesising new molecules and improve existing systems. We need many new revolutionary molecules and biocatalysts for a plethora of chemical reactions and industrial applications

Effect of Alcohol Structure on the Optimum Condition for Novozym 435-Catalyzed Synthesis of Adipate Esters

Immobilized Candida antarctica lipase B, Novozym 435, was used as the biocatalyst in the esterification of adipic acid with four different isomers of butanol (n-butanol, sec-butanol, iso-butanol, and tert-butanol). Optimum conditions for the synthesis of adipate esters were obtained using response surface methodology approach with a four-factor-five-level central composite design concerning important reaction parameters which include time, temperature, substrate molar ratio, and amount of enzyme. Reactions under optimized conditions has yielded a high percentage of esterification (>96%) for n-butanol, iso-butanol, and sec-butanol, indicating that extent of esterification is independent of the alcohol structure for primary and secondary alcohols at the optimum conditions. Minimum reaction time (135 min) for achieving maximum ester yield was obtained for iso-butanol. The required time for attaining maximum yield and also the initial rates in the synthesis of di-n-butyl and di-sec-butyl adipate were nearly the same. Immobilized Candida antarctica lipase B was also capable of esterifying tert-butanol with a maximum yield of 39.1%. The enzyme is highly efficient biocatalyst for the synthesis of adipate esters by offering a simple production process and a high esterification yield

Optimization and characterization of lipase catalysed synthesis of xylose caproate ester in organic solvents

The lipase catalysed synthesis of xylose caproate ester was performed by condensation of xylose, an aldopentose and caproic acid in organic solvents. A dual-solvent system containing DMSO and acetone (1:10 v/v) was used to determine the optimal conditions for the reaction. Different reaction parameters (solvent system, reaction time, substrate molar ratio and the amount of enzyme loaded) were studied. The highest conversion rate (64%) was obtained within 24 h with the optimal conditions of 16% (w/v) Novozym 435 and a molar ratio of xylose to caproic acid of 1:4

Fuzzy modeling and optimization of biochemical processes: a case study

This paper presents an application of a neuro-fuzzy modeling approach in order to characterize essential behavior of biological processes. The gathered information from experiments was employed to develop a fuzzy model for an enzyme-catalyzed esterification process. The accuracy of developed model was validated by comparing the response of the model and actual data from experiments. A model-based optimization was preformed to obtain the best operating conditions by using the developed model for esterification process. The optimization was carried out for global and constrained solutions. The obtained results show the accuracy and feasibility of proposed algorithm for optimization of biological processes

Lipase catalysed synthesis of adipate wax esters in ionic liquid

Adipate wax ester shows excellent properties such as its low toxicity, good thermal stability, low volatility and high biodegradability, which made it as a very useful compound and significant to various industrial applications including pharmaceutical, food and coating. Green route organic synthesis via enzymatic synthesis, offers clean and mild reaction conditions provides an opportunity to increase productivity, efficiency and quality output. Considering the industrial importance of the ester, the optimal conditions for upscaling process was performed using Response Surface Methodology (RSM). Ionic liquid of [bmim]PF6 was used as a solvent in the esterification of different chain length of alcohol with adipic acid, and Novozyme as a biocatalyst. Higher percentage of yield (>80%) was obtained for longer alcohol chain (dioleyl adipate) but slightly lower yields were found for medium alcohol chain than in hexane. Ionic liquid become the major interest as it can recycled and remained the efficiency once compared to conventional organic solvent

Structure-based and ligand-based virtual screening of novel methyltransferase inhibitors of the dengue virus.

The dengue virus is the most significant arthropod-borne human pathogen, and an increasing number of cases have been reported over the last few decades. Currently neither vaccines nor drugs against the dengue virus are available. NS5 methyltransferase (MTase), which is located on the surface of the dengue virus and assists in viral attachment to the host cell, is a promising antiviral target. In order to search for novel inhibitors of NS5 MTase, we performed a computer-aided virtual screening of more than 5 million commercially available chemical compounds using two approaches: i) structure-based screening using the crystal structure of NS5 MTase and ii) ligand-based screening using active ligands of NS5 MTase. Structure-based screening was performed using the LIDAEUS (LIgand Discovery At Edinburgh UniverSity) program. The ligand-based screening was carried out using the EDULISS (EDinburgh University LIgand Selection System) program. The selection of potential inhibitors of dengue NS5 MTase was based on two criteria: the compounds must bind to NS5 MTase with a higher affinity than that of active NS5 MTase ligands, such as ribavirin triphosphate (RTP) and S-adenosyl-L-homocysteine (SAH); and the compounds must interact with residues that are catalytically important for the function of NS5 MTase. We found several compounds that bind strongly to the RNA cap site and the S-adenosyl-L-methionine (SAM) binding site of NS5 MTase with better binding affinities than that of RTP and SAH. We analyzed the mode of binding for each compound to its binding site, and our results suggest that all compounds bind to their respective binding sites by interacting with, and thus blocking, residues that are vital for maintaining the catalytic activity of NS5 MTase. We discovered several potential compounds that are active against dengue virus NS5 MTase through virtual screening using structure-based and ligand-based methods. These compounds were predicted to bind into the SAM binding site and the RNA cap site with higher affinities than SAH and RTP. These compounds are commercially available and can be purchased for further biological activity tests

Regional valuation of infrastructure improvements. The case of Swedish road freight

Is it possible to identify regional differences among shippers in their valuation of infrastructure improvements? The question is analysed within a random utility approach where parameters are estimated by a logit model. Data consists of a Swedish stated preference study from 1992. The results indicate that regional differences may exist but a considerable heterogeneity in the empirical material prohibit robust results in some cases. However, regional differences seem to exist when industrial mix, shipping distance and goods values are held constant. Independent of the limitations, the results should render implications to any infrastructure benefit analysis where parameters from spatial averages are used. The results are based on short term decisions and one should recognise that parameters may vary under mid- and long- term.Regional preferences; road transportation; freight demand; stated preference analysis; random utility models; logit model

Biophysical properties of DNA in hydrated ionic liquids

The biophysical properties and behavior of natural calf thymus DNA in hydrated 1-ethyl-3-butylimidazolium bromide ionic liquid ([C2bim]Br) have been studied using spectroscopy technique. The effect of ionic liquid concentration and temperature towards the duplex B-DNA conformation were determined. The presence of ionic liquid causes higher duplex DNA stability with the DNA melting temperature of ∼56°C without any addition of buffer solutions. The electrostatic attraction between ionic liquid’s cation and DNA phosphates groups was found play a main role in stabilizing native DNA structure. Understanding of the biophysical properties of DNA in this ionic media could be used as a platform for future development of specific solvent for nucleic acid nanotechnology

Pretreatment of oil palm trunk in deep eutectic solvent and optimization of enzymatic hydrolysis of pretreated oil palm trunk

Deep eutectic solvents (DES) were utilised as pretreatment media on oil palm trunk (OPT) fibre in order to change the morphology of the highly crystalline cellulose prior to enzymatic hydrolysis. Among all the DESs tested, ethylammonium chloride: ethylene glycol (EAC:EG) was found to be the most efficient solvent for the pretreatment of OPT fibre. The pretreatment of OPT by EAC:EG had removed 42% lignin and 83% hemicellulose with the ability to dissolve the OPT biomass (58%) after heating at 100 °C for 48 h. FTIR analysis was used in determining the chemical characteristic changes where OPT treated in EAC:EG had more disruption of hydroxyl bond and indication of delignification compared to OPT treated with other DESs. Enzymatic hydrolysis was carried out on OPT treated in EAC:EG and the highest glucose production (74%) was achieved at 50 °C after 24 h with 15 mg/mL substrate concentration, 50 FPU/g of Celluclast 1.5 L and 100 CBU/ml of Novozyme 188

Modeling and optimization of lipase-catalyzed production of succinic acid ester using central composite design analysis.

Esterification of succinic acid with oleyl alcohol catalyzed by immobilized Candida antarctica lipase B (Novozym 435) was investigated in this study. Response surface methodology (RSM) based on a five-level, four-variable central composite design (CCD) was used to model and analyze the reaction. A total of 21 experiments representing different combinations of the four parameters including temperature (35–65°C), time (30–450 min), enzyme amount (20-400 mg), and alcohol:acid molar ratio (1:1-8:1) were generated. A partial cubic equation could accurately model the response surface with a R2 of 0.9853. The effect and interactions of the variables on the ester synthesis were also studied. Temperature was found to be the most significant parameter that influenced the succinate ester synthesis. At the optimal conditions of 41.1°C, 272.8 min, 20 mg enzyme amount and 7.8:1 alcohol:acid molar ratio, the esterification percentage was 85.0%. The model can present a rapid means for estimating the conversion yield of succinate ester within the selected ranges