Kinetic modeling and docking study of immobilized lipase catalyzed synthesis of furfuryl acetate

Coffee Roasting and Extraction as a Factor in Cold Brew Coffee Quality

Due to the dynamic growth of the cold brew coffee market, the aim of this study was to identify and characterize main bioactive and aromatic compounds that may be helpful for quality control during the production of popular beverages. Using headspace solid-phase microextraction and GC-MS and LC-MS analysis, prepared cold brew coffee extracts were investigated and compared with different green bean roasting profiles and varying extraction temperature and time parameters. In terms of quantitative composition, the study showed that cold brew coffees are an exceptional source of chlorogenic acid. Therefore, they may change consumers purchasing decisions on the beverage market and establish a new and natural substitute for controversial energy drinks. The analyses confirm the possibility of producing a beverage with increased chlorogenic acid content above 900 mg/L or at a similar level of 400–500 mg/L with caffeine, which may be important on an industrial scale due to the possibility of diversifying beverage production. Furthermore, aroma compounds were presented as markers responsible for fruity or caramel–roasted-almond notes and changes in their concentrations according to the recipe were also presented. The best option for cold brew coffee production appears to be beans roasted in the 210–220 °C temperature range.

Synthesis of propyl benzoate by solvent-free immobilized lipase-catalyzed transesterification: Optimization and kinetic modeling

The present study aimed to analyze reaction kinetics and mechanism for the synthesis of propyl benzoate in solvent-free conditions. Lipase was immobilized on Hydroxypropyl methylcellulose (HPMC) and polyvinyl alcohol (PVA) polymer blend by entrapment method. Among different lipases immobilized on a support, Candida cylindracea (CCL) showed excellent activity. Systematic studies were done to optimize the reaction conditions. The activation energy was found to be 16.2 kcal/mol for immobilized CCL. Kinetic parameters were calculated, which depicted that propyl benzoate synthesized using immobilized CCL followed the ternary complex model in which propanol inhibits lipase activity at higher concentrations. Recyclability of the catalyst was checked up to four catalytic cycles and 40% retention of activity was observed up to the fourth cycle. Finally, the applicability of developed protocol to synthesize various alkyl benzoates was explored.

A one-pot process for synthesis of mitomycin analogs catalyzed by laccase/lipase optimized by response surface methodology

To reach the excellent yield as well as environmental friendliness, an efficient one‐pot process for the synthesis of 2‐methyl‐3‐n‐butylaminoyl‐1,4‐benzoquinone, a mitomycin‐like compound by the domino reaction of 2‐methyl‐1,4‐hydroquinone and butylamine using laccase/lipase as co‐catalysts, has been developed. In this present study, the process proposed here was further improved by optimizing the relevant factors using the response surface methodology based on Box–Benkhen Design. The optimum condition that afforded the highest yield (98%) of 2‐methyl‐3‐n‐butylaminoyl‐1,4‐benzoquinone was obtained as follows: molar ratio of amines to hydroquinones 1.16:1, activity ratio of laccase to lipase 1.14:2, and reaction temperature 38.9°C. The results obtained indicate that this process may be useful as a green alternative method for higher yield production of mitomycin analogs.

Optimization of chemoenzymatic Baeyer-Villiger oxidation of cyclohexanone to ε-caprolactone using response surface methodology

ε-Caprolactone (ε-CL) has attracted a great deal of attention and a high product concentration is of great significance for reducing production cost. The optimization of ε-CL synthesis through chemoenzymatic Baeyer-Villiger oxidation mediated by immobilized Trichosporon laibacchii lipase was studied using response surface methodology (RSM). The yield of ε-CL was 98.06% with about 1.2 M ε-CL concentration that has a substantial increase mainly due to both better stability of the cross-linked immobilized lipase used and the optimum reaction conditions in which the concentration of cyclohexanone was 1.22 M, the molar ratio of cyclohexanone:urea hydrogen peroxide (UHP) was 1:1.3, and the reaction temperature was 56.5°C. Based on our experimental results, it can be safely concluded that there are three reactions in this reaction system, not just two reactions, in which the third reaction is that the acetic acid formed reacts with UHP to form peracetic acid in situ catalyzed by the immobilized lipase. A quadratic polynomial model based on RSM experimental results was developed and the R² value of the equation is 0.9988, indicating that model can predict the experimental results with high precision. The experimental results also show that the molar ratio of cyclohexanone to UHP has very significant impact on the yield of ε-CL (p < .0006).

Highly efficient synthesis of arbutin esters catalyzed by whole cells ofCandida parapsilosis

Acylation modification of phenol glycosides is currently of great interest due to the improved bioavailability and multiple functions.