Operational stability of naringinase PVA lens-shaped microparticles in batch stirred reactors and mini packed bed reactors-one step closer to industry

Reactor Selection for Effective Continuous Biocatalytic Production of Pharmaceuticals

Enzyme catalyzed reactions are rapidly becoming an invaluable tool for the synthesis of many active pharmaceutical ingredients. These reactions are commonly performed in batch, but continuous biocatalysis is gaining interest in industry because it would allow seamless integration of chemical and enzymatic reaction steps. However, because this is an emerging field, little attention has been paid towards the suitability of different reactor types for continuous biocatalytic reactions. Two types of continuous flow reactor are possible: continuous stirred tank and continuous plug-flow. These reactor types differ in a number of ways, but in this contribution, we focus on residence time distribution and how enzyme kinetics are affected by the unique mass balance of each reactor. For the first time, we present a tool to facilitate reactor selection for continuous biocatalytic production of pharmaceuticals. From this analysis, it was found that plug-flow reactors should generally be the system of choice. However, there are particular cases where they may need to be coupled with a continuous stirred tank reactor or replaced entirely by a series of continuous stirred tank reactors, which can approximate plug-flow behavior. This systematic approach should accelerate the implementation of biocatalysis for continuous pharmaceutical production.

Hydrogel/enzyme dots as adaptable tool for non-compartmentalized multi-enzymatic reactions in microfluidic devices

Validating the robustness and activity of hydrogel/enzyme dots as adaptable tool for non-compartmentalized multi-enzymatic reactions in microfluidic devices under continuous flow.

Exploring magnetic and imprinted cross-linked enzyme aggregates of rhamnopyranosidase in microbioreactors

The goal of this work was the development of magnetic cross link enzyme aggregates (mCLEAs) of rhamnopyranosidase (Rhmnase), prepared by chemical cross-linking with functionalized magnetite nanoparticles for glycompounds biosynthesis in microbioreactors (specially design 24-well microplate and mini-packed bed). Rhamnopyranosidase (EC number 3.2.1.40) present high potential in glycocompounds production, with applications in food and pharmaceutical industries. The influence of precipitants, cross-linkers, temperature and time on (m)CLEAs@Rhmnase development were optimized. Biocatalyst activity was accessed in the hydrolysis of 4',5,7-trihydroxyflavanone-7-rhamnoglucoside and kinetic constants in the deglycosylation reaction were evaluated. Rhmnase operational stability was enhanced in mCLEAs, retaining almost 90% initial activity after 7 cycles of 24 h each. In a mini-packed bed bioreactor a maximum volumetric productivity of 140 μmol/L.h was attained. In this bioreactor the operational stability of mCLEAs@Rhmnase were evaluated at a flow rate of 5 mL/h during 5 days and a residual activity of 95% was observed.

Improved thermostable polyvinyl alcohol electrospun nanofibers with entangled naringinase used in a novel mini-packed bed reactor

Polyvinyl alcohol (PVA) electrospun nanofibers were produced using an electrospinning technique. Key parameters (e.g. collectors, distance from needle tip to collector, among others) that influence the structure and morphology of fibers were optimized. The naringinase entrapped in PVA nanofibers retained over 100% of its initial activity after 212h of operation, at 25°C. Chemical crosslinking with several boronic acids further increased the hydrolysis temperature (up to 85°C) and yielded nanofibers with thermal stability up to 121°C. A mini packed bed reactor (PBR) developed to establish the feasibility for continuous enzymatic operation, ran for 16days at 45°C. Highest naringenin biosynthesis was attained at a flow rate of 10mLh(-1). Highest volumetric (78molL(-1)h(-1)) and specific (26molh(-1)genzyme(-1)) productivities were attained at 30mLh(-1). The activity of NGase in electrospun nanofibers remained constant for almost 16days of operation at 10mLh(-1).

Scale-up of naringinase production process based on the constant oxygen transfer rate for a novel strain of Bacillus methylotrophicus

Naringinase bioprocess based on Bacillus methylotrophicus was successfully scaled up based on constant oxygen transfer rate (OTR) as the scale-up criterion from 5-L bioreactor to 20-L bioreactor. OTR was measured in 5 and 20-L bioreactor under various operating conditions using dynamic method. The operating conditions, where complete dispersion was observed were identified. The highest OTR of 0.035 and 0.04 mMol/L/s was observed in 5 and 20-L bioreactor, respectively. Critical dissolved oxygen concentration of novel isolated strain B. methylotrophicus was found to be 20% of oxygen saturation in optimized medium. The B. methylotrophicus cells grown on sucrose had maximum oxygen uptake rate of 0.14 mMol/L/s in optimized growth medium. The cells produced the maximum naringinase activity of 751 and 778 U/L at 34 hr in 5 and 20-L bioreactors, respectively. The maximum specific growth rate of about 0.178/hr was observed at both the scales of operations. The maximum naringinase yield of 160 and 164 U/g biomass was observed in 5 and 20-L bioreactors, respectively. The growth and production profiles at both scales were similar indicating successful scale-up strategy for B. methylotrophicus culture.