RESUMEN
Biocatalysis has emerged as a strong tool for the synthesis of active pharmaceutical ingredients (APIs). In the early twentieth century, whole cell biocatalysis was used to develop the first industrial biocatalytic processes, and the precise work of enzymes was unknown. Biocatalysis has evolved over the years into an essential tool for modern, cost-effective, and sustainable pharmaceutical manufacturing. Meanwhile, advances in directed evolution enable the rapid production of process-stable enzymes with broad substrate scope and high selectivity. Large-scale synthetic pathways incorporating biocatalytic critical steps towards >130 APIs of authorized pharmaceuticals and drug prospects are compared in terms of steps, reaction conditions, and scale with the corresponding chemical procedures. This review is designed on the functional group developed during the reaction forming alcohol functional groups. Some important biocatalyst sources, techniques, and challenges are described. A few APIs and their utilization in pharmaceutical drugs are explained here in this review. Biocatalysis has provided shorter, more efficient, and more sustainable alternative pathways toward existing small molecule APIs. Furthermore, non-pharmaceutical applications of biocatalysts are also mentioned and discussed. Finally, this review includes the future outlook and challenges of biocatalysis. In conclusion, Further research and development of promising enzymes are required before they can be used in industry.
Asunto(s)
Alcoholes , Biocatálisis , Alcoholes/metabolismo , Alcoholes/química , Preparaciones Farmacéuticas/metabolismo , Preparaciones Farmacéuticas/síntesis química , Preparaciones Farmacéuticas/química , Estereoisomerismo , Enzimas/metabolismo , Industria FarmacéuticaRESUMEN
Hydrogen production by cyanobacteria could be one of the promising energy resources in the future. However, there is very limited information regarding the kinetic modeling of hydrogen production by cyanobacteria available in the literature. To provide an in-depth understanding of the biological system involved during the process, the Haldane's noncompetitive inhibition equation has been modified to determine the specific hydrogen production rate (HPR) as a function of both dissolved CO2 concentration (CTOT) and oxygen production rate (OPR). The highest HPR of 15 [Formula: see text] was found at xCO2 of 5% vol/vol and the rate consequently decreased when the CTOT and OPR were 0.015 k mol m-3 and 0.55 mL h-1, respectively. The model provided a fairly good estimation of the HPR with respect to the experimental data collected.
Asunto(s)
Anabaena/metabolismo , Dióxido de Carbono/metabolismo , Hidrógeno/metabolismo , Oxígeno/metabolismo , CinéticaRESUMEN
This work investigates the effect of heterocyst toward biohydrogen production by A. variabilis. The heterocyst frequency was artificially promoted by adding an amino acid analog, in this case DL-7-azatryptophan into the growth medium. The frequency of heterocyst differentiation was found to be proportional to the concentration of azatryptophan (0-25 µM) in the medium. Conversely, the growth and nitrogenase activity were gradually suppressed. In addition, there was also a distinct shortening of the cells filaments and detachment of heterocyst from the vegetative cells. Analysis on the hydrogen production performance revealed that both the frequency and distribution of heterocyst in the filaments affected the rate of hydrogen production. The highest hydrogen production rate and yield (41 µmol H2 mg chl a(-1) h(-1) and 97 mL H2 mg chl a(-1), respectively) were achieved by cells previously grown in 15 µM of azatryptophan with 14.5 % of heterocyst frequency. The existence of more isolated heterocyst has been shown to cause a relative loss in nitrogenase activity thus lowering the hydrogen production rate.
Asunto(s)
Cianobacterias/citología , Cianobacterias/metabolismo , Hidrógeno/metabolismo , Medios de Cultivo/química , Cianobacterias/efectos de los fármacos , Cianobacterias/enzimología , Nitrogenasa/metabolismo , Triptófano/análogos & derivados , Triptófano/farmacologíaRESUMEN
The intrinsic growth, substrate uptake, and product formation biokinetic parameters were obtained for the anaerobic bacterium, Clostridium ljungdahlii, grown on synthesis gas in various pressurized batch bioreactors. A dual-substrate growth kinetic model using Luong for CO and Monod for H2 was used to describe the growth kinetics of the bacterium on these substrates. The maximum specific growth rate (µ(max) = 0.195 h(-1)) and Monod constants for CO (K s,CO = 0.855 atm) and H2 (K(s,H2) = 0.412 atm) were obtained. This model also accommodated the CO inhibitory effects on cell growth at high CO partial pressures, where no growth was apparent at high dissolved CO tensions (P(CO)(∗) > 0.743 atm). The Volterra model, Andrews, and modified Gompertz were, respectively, adopted to describe the cell growth, substrate uptake rate, and product formation. The maximum specific CO uptake rate (q(max) = 34.364 mmol/g cell/h), CO inhibition constant (K(I) = 0.601 atm), and maximum rate of ethanol (R(max) = 0.172 mmol/L/h at P(CO) = 0.598 atm) and acetate (R(max) = 0.096 mmol/L/h at P(CO) = 0.539 atm) production were determined from the applied models.
Asunto(s)
Biocombustibles , Clostridium/metabolismo , Fermentación , Gases/metabolismo , CinéticaRESUMEN
The present work aims to address the gas-phase biotransformation of geraniol into citronellol using growing cells of Saccharomyces cerevisiae (baker's yeast) in a continuous-closed-gas-loop bioreactor (CCGLB). This study revealed that the gaseous geraniol had a severe effect on the production of biomass during the growing cell biotransformation resulting in the decrease in the specific growth rate from 0.07 to 0.05 h⻹. The rate of reaction of the growing cell biotransformation was strongly affected by agitation and substrate flow rates. The highest citronellol concentration of 1.18 g/L and initial rate of reaction of 7.06 × 10â»4 g/min g(cell) were obtained at 500 rpm and 8 L/min, respectively.
Asunto(s)
Reactores Biológicos , Monoterpenos/metabolismo , Saccharomyces cerevisiae/crecimiento & desarrollo , Saccharomyces cerevisiae/metabolismo , Monoterpenos Acíclicos , Biomasa , Biotransformación/fisiología , Cromatografía de Gases , Fermentación , Espectrofotometría , Terpenos/metabolismoRESUMEN
Terpenes and terpenoids are among the key impact substances in the food and fragrance industries. Equipped with pharmacological properties and applications as ideal precursors for the biotechnological production of natural aroma chemicals, interests in these compounds have been escalating. Hence, the syntheses of new derivatives that can show improved properties are often called for. Stereoselective biotransformation offers several benefits to increase the rate of production, in terms of both the percentage yield and its enantiomeric excesses. Baker's yeast (Saccharomyces cerevisiae) is broadly used as a whole cell stereospecific reduction biocatalyst, due to its capability in reducing carbonyls and carbon-carbon double bonds, which also extends its functionality as a versatile biocatalyst in terpenoid biotransformation. This review provides some insights on the development and prospects in the reductive biotransformation of monoterpenoids and sesquiterpenoids using S. cerevisiae, with an overview of strategies to overcome the common challenges in large-scale implementation.
Asunto(s)
Monoterpenos/metabolismo , Saccharomyces cerevisiae/metabolismo , Sesquiterpenos/metabolismo , Biotransformación , Oxidación-ReducciónRESUMEN
In order to characterize enzyme activity and stability corresponding to temperature effects, thermodynamic studies on commercial immobilized lipase have been carried out via enzymatic transesterification. An optimum temperature of 40 degrees C was obtained in the reaction. The decreasing reaction rates beyond the optimum temperature indicated the occurrence of reversible enzyme deactivation. Thermodynamic studies on lipase denaturation exhibited a first-order kinetics pattern, with considerable stability through time shown by the lipase as well. The activation and deactivation energies were 22.15 kJ mol(-1) and 45.18 kJ mol(-1), respectively, implying more energy was required for the irreversible denaturation of the enzyme to occur. At water content of 0.42%, the initial reaction rate and FAME yield displayed optimum values of 3.317 g/L min and 98%, respectively.
Asunto(s)
Biocombustibles , Enzimas Inmovilizadas/metabolismo , Lipasa/metabolismo , Termodinámica , Biocatálisis , Cromatografía de Gases , Esterificación , Cinética , Lipasa/antagonistas & inhibidores , TemperaturaRESUMEN
This review tracks a decade of dynamic kinetic resolution developments with a biocatalytic inclination using enzymatic/microbial means for the resolution part followed by the racemization reactions either by means of enzymatic or chemocatalyst. These fast developments are due to the ability of the biocatalysts to significantly reduce the number of synthetic steps which are common for conventional synthesis. Future developments in novel reactions and products of dynamic kinetic resolutions should consider factors that are needed to be extracted at the early synthetic stage to avoid inhibition at scale-up stage have been highlighted.