Recovery and separation of glycyrrhizic acid from Natural Deep Eutectic Solvent (NADES) extract by macroporous resin: adsorption kinetics and isotherm studies.

Natural Deep Eutectic Solvents (NADESs) have emerged as a green and sustainable alternative to conventional organic solvents to extract bioactive compounds. However, the recovery of bioactive compounds from the NADES extracts is challenging, restricting their large-scale applications. The present work investigated the recovery of glycyrrhizic acid (GA) from choline-chloride/lactic acid NADES extract using macroporous resins. GA possesses a wide spectrum of biological activities, and it is extracted from the well-known herb Glycyrrhiza glabra. During resin screening, DIAIONTM SP700 showed high adsorption and desorption capacities. The adsorption kinetics study demonstrated that the adsorption of GA on SP700 followed Pseudo First-order kinetic model. Moreover, the adsorption behaviors were elucidated by the Freundlich isotherm using a correlation coefficient based on a static adsorption study at different temperatures and pH. Furthermore, the thermodynamic parameters, for instance, the change of Gibbs free energy (ΔG*), entropy (ΔS*), and enthalpy (ΔH*), showed that the adsorption process was spontaneous, favorable and exothermic. In addition, the sample after macroporous resin treatment, which is enriched with GA exhibited good anticancer potential analyzed by SRB assay. The regenerated NADES solvent was recycled twice, keeping more than 90% extraction efficiency, indicating good reusability of NADES in the GA extraction process by using macroporous resin.

Process Intensification of Enzymatic Synthesis of Flavor Esters: A Review.

The conventional flavor synthesis method suffers from low yields, time inefficiency, and extreme reaction conditions. Therefore, there is a necessity for the green and novel synthesis approach to overcome these limitations. The current review presents a holistic insight into different aspects associated with the synthesis of flavor esters using the immobilized enzyme. The application of process intensification tools such as ultrasound and microwave irradiation can enhance the reaction efficiency because of higher product recovery, less formation of by-products, and decreased energy consumption. This review presents the process intensification of value-added flavor esters synthesis and the mechanism of ultrasound and microwave action on the enzyme to enhance the enzyme activity and increase the reaction rate. It also summarizes the role of process intensification in enzymatic flavor ester synthesis, followed by specific examples as reported in the literature.

Evaluation of nutritional and medicinal potential of defatted Sapindus mukorossi seed kernel.

This work deals with the evaluation of nutritional and medicinal potential of a defatted kernel of Sapindus mukorossis seed. Defatted sapindus seed kernel is a rich source of proteins (33.4 ± 2.12%), which show balanced amino acid composition for the requirement of adults as per the World Health Organization. Protein isolate possesses 29 kDa molecular weight peptide, which shows trypsin inhibitor activity. It also showed around 31.2% reduction in amylase activity while aqueous Ethanol and ethanol extracts showed 55% and 72.83%, respectively. Aqueous ethanol and ethanol extracts were found to contain polyphenols and saponins. Polyphenol content in aqueous ethanol and ethanol extract was 4.50 ± 0.15 mg/g and 5.7 ± 0.34 mg/g ferulic acid equivalent, respectively, while 0.72 ± 0.68% and 1.2 ± 0.23% Oleonolic acid equivalent saponins, respectively. Both these extracts showed potent antioxidant activity, and the rate of DPPH scavenging activity was higher than the ferulic acid standard. The deffated seed also contains dietary fibers in which 3.8 ± 0.01% are soluble, and 2.2 ± 0.03% are insoluble fibers.

Extraction of total antioxidants from Azadirachta indica (neem) using three phase partitioning and its process intensification using ultrasound.

The majority of the naturally occurring antioxidants are obtained from plant sources. The antioxidant activity is mostly exhibited by polyphenols present in the plant cells. Azadirachta Indica (Neem) leaves are renowned for their medicinal applications due to their anti-inflammatory, antimalarial, antifungal, antibacterial, antiviral, antioxidant, and anticarcinogenic properties. This work aims to optimize the extraction of Azadirachta Indica (Neem) leaf antioxidants using three-phase partitioning (TPP). The optimized conditions are operating time 15 minutes, slurry ratio 1:30 (g/mL), salt concentration 30% (w/v), aqueous to solvent ratio 1:1.5 (v/v), and stirring speed 400 rpm that infer 74.66% extraction yield. Additionally, ultrasonic pretreatment was also employed to increase the extraction yield up to 86.61%. Sonication pretreatment for 4 min operated at 30 W power, and 75% duty cycle was observed to offer maximum antioxidant extraction about 3.3 mg/g.

Integrated strategies for enzyme assisted extraction of bioactive molecules: A review.

Conventional methods of extracting bioactive molecules are gradually losing pace due to their numerous disadvantages, such as product degradation, lower efficiency, and toxicity. Thus, in light of the rising demand for these bioactive, enzymes have garnered much attention for their efficiency in extraction. However, enzyme-assisted extraction is also plagued with a high capital cost that cannot justify the extraction yields obtained. In order to mitigate these problems, enzyme-assisted extraction can be consorted with non-conventional methods. This review includes current progress concerning the combined approaches while converging the recent advancements in the field that outperformed conventional extraction processes. It also highlights the design of biocatalyst and key parameters involved in the effective extraction of bioactive molecules. An integrated approach for efficiently extracting polyphenols, essential oils, pigments, and vitamins has been comprehensively reviewed. Furthermore, the different immobilization strategies have been discussed for large-scale implementation of enzymes for extraction. The integration of advanced non-conventional methods with enzyme-assisted extraction will open new avenues to enhance the overall extraction efficiency.

Intensification of Enzymatic Synthesis of Decyl Oleate Using Ultrasound in Solvent Free System: Kinetic, Thermodynamic and Physicochemical Study.

The present study evaluates the potential use of ultrasound irradiation to synthesize decyl oleate using Fermase CALBTM10000 under the solvent-free system (SFS). The optimal condition to achieve a maximum yield of 97.14% was found to be 1:2 oleic acid:decanol ratio, 1.8% (w/w) enzyme loading, 45°C temperature, 200 rpm agitation speed, 50 W power input, 50% duty cycle, 22 kHz frequency and reaction time of 25 minutes. The thermodynamic study was done to determine the change in entropy, Gibb's free energy, and change in enthalpy at various temperatures. The experimental results and kinetic study showed that the reaction followed ordered bi-bi model with kinetic parameters as rate of reaction (V max ) = 35.02 M/min/g catalyst, Michaelis constant for acid (K A ) = 34.47 M, Michaelis constant for alcohol (K B ) = 3.31 M, Inhibition constant (Ki) = 4542.4 M and sum of square error (SSE) = 0.000334. The application of ultrasound irradiation combined with biocatalyst and the absence of solvent intensified the process compared to the traditional stirring method using hexane as solvent.

Valorization of waste Syzygium cumini seed kernels by three-phase partitioning extraction and evaluation of in vitro antioxidant and hypoglycemic potential.

Diabetes is one of the leading causes of morbidity and mortality worldwide. Replacement of the chemically synthesized medicines with phytomedicines is of great importance. Syzygium cumini fruit has around 30% hard seed kernel part that is considered solid waste and can be a good source of bioactive phenolic compounds. Thus, this work was performed to valorize Syzygium cumini kernels powder (SCKP) using a three-phase partitioning technique (TPP) and evaluate in vitro antioxidant and hypoglycemic activities. The extraction yield of catechin, gallic acid, TFC, and TPC obtained through TPP was 0.52, 33.24 mg/g, 7.78 mg CE/g, and 82.66 mg GAE/g, respectively, in 45 min, 40% ammonium sulfate, 1:1 (V/V) extraction slurry to t-butanol, 30 ± 2 °C temperature, pH 4, 1:20 (g/mL) SCKP to water and SCKP size 106 µm. IC50 values 12.15, 9.33, and 7.55 in µg/mL for TPP extract were obtained from DPPH, α-amylase, and α-glucosidase in vitro assays, respectively. TPP for extraction of bioactive compounds was found superior over traditional extraction techniques (devoid of t-butanol and ammonium sulfate). The extract obtained shows enormous antioxidant and hypoglycemic potential for use in nutraceutical and pharmaceutical industries.HighlightsFirst report on three-phase partitioning (TPP) extraction of catechin and gallic acid from SCKP.Effective extraction of total phenolic and flavonoid compounds.Proved the enormous antioxidant and hypoglycemic potential of SCKP's TPP extract.TPP extraction, the selective, efficient, and economically viable option.

Optimization and kinetic study of ultrasound assisted deep eutectic solvent based extraction: A greener route for extraction of curcuminoids from Curcuma longa.

The use of deep eutectic solvents (DESs) as a new extraction medium is a step towards the development of green and sustainable technology. In the present study, nine DESs based on choline chloride acids, alcohols, and sugar were screened to study the extraction of curcuminoids from Curcuma longa L. Choline chloride and lactic acid DES at 1:1 M ratio gave the maximum extent of extraction. Further, DES based extraction was intensified using ultrasound. The impact of various process parameters such as % (v/v) water in DES, % (w/v) solid loading, particle size, ultrasound power intensity, and pulse mode operation of ultrasound was studied. The maximum curcuminoids yield of 77.13 mg/g was achieved using ultrasound assisted DES (UA-DES) based extraction in 20% water content DES at 5% solid loading and 0.355 mm particle size with 70.8 W/cm2 power intensity and 60% (6 sec ON and 4 sec OFF) duty cycle at 30 ± 2 °C in 20 min of irradiation time. Kinetics of UA-DES extraction was explained using Peleg's model and concluded that it is compatible with the experimental data. Additionally, anti-solvent (water) precipitation technique was applied, which resulted in 41.97% recovery of curcuminoids with 82.22% purity from UA-DES extract in 8 h of incubation at 0 °C. The comparison was made between conventional Soxhlet, batch, DES and UA-DES based processes on the basis of yield, time, solvent requirement, temperature, energy consumption, and process cost. The developed UA-DES based extraction can be an efficient, cost effective, and green alternative to conventional solvent extraction for curcuminoids.

Rapid extraction of watermelon seed proteins using microwave and its functional properties.

Solid food industry waste like watermelon seed is an excellent source of value-added components such as proteins, oil, and carbohydrate. In the present study, protein extraction was carried out using microwave energy from defatted watermelon seeds (DWS), containing 50% of proteins. Microwave-assisted extraction (MAE) was optimized with different parameters, namely, solid to solvent ratio (1:10-1:40), pH (7-10), microwave power (30 W, 50 W, 70 W), extraction time (30 s-8 min) and moisture content or pre-leaching effect. Maximum protein recovery was achieved with 50 W microwave power, solid to solvent ration of 1:30, and pH 10 in 2 minutes of microwave irradiation time. MAE gave higher yield in less time compared to conventional extraction. SDS-PAGE confirmed the molecular weight of watermelon seed proteins (WSP) in the range of 25-250 kDa. A comparative study showed 90% protein recovery with MAE in 2 min with 1:30 (w/v) solid to solvent ratio, whereas ultrasound gave 87% in 9 min with 1:50 (w/v) ratio and batch 72% in 25 min with 1:70 (w/v) ratio. Watermelon seed proteins obtained from MAE method possess excellent functional properties with reference to conventional extraction method indicating its application in food products.

Antidiabetic potential evaluation of aqueous extract of waste Syzygium cumini seed kernel's by in vitro α-amylase and α-glucosidase inhibition.

Syzygium cumini, owing to higher bioactive constituents, its parts principally kernels are used for the antidiabetic purpose since the olden days. The current manuscript illustrated batch extraction of phenolic compounds from S. cumini using a stirred extractor. The yields 0.61 mg/g, 35.9 mg/g, 79.89 mg GAE/g, and 7.29 mg CE/g of catechin, gallic acid, TPC and TFC, respectively, were obtained in 105 min. at 1:20 SCKP to water, 50 ± 2 °C temperature, 4 pH, at 250 rpm and 106 µm particle size of SCKP. In vitro evaluation of the antioxidant and antidiabetic potential of the obtained aqueous extract was carried out by DPPH, α-amylase, and α-glucosidase inhibitory assays. The IC50 values of SCKP aqueous extract obtained were 12.97, 9.03, and 7.13 µg/mL for DPPH scavenging, inhibition of α-amylase, and α-glucosidase, respectively. The cost required to extract 1 kg of catechin, gallic acid, TPC, and TFC was Rs 6691.6, 113.7, 51.1, and 559.93/-, respectively. Stirred batch extraction technique manifests traditional but simple, ecofriendly, and efficient compared to other traditional techniques. The output of this research bestows support to utilize the SCKP stirred batch extract as a promising source of antioxidant and antidiabetic compounds in ayurvedic formulations.

Ultrasound Assisted Green Synthesis of 2-Ethylhexyl Stearate: A Cosmetic Bio-lubricant.

The 2-ethylhexyl stearate is used as a bio-lubricant in various cosmetic products. The present study is focused on the biocatalyzed esterification of 2-ethylhexanol and stearic acid to form 2-ethylhexyl stearate catalyzed by Fermase CALB 10000 in the presence of ultrasound treatment. The maximum conversion (95.87%) was obtained at molar ratio of 2-ethylhexanol to stearic acid 2:1, enzyme amount of 2 % (w/w), power 80 W, duty cycle 50 % and temperature 50°C in comparatively short reaction time (3 h) in the presence of Fermase as a catalyst. At optimum conditions, it is observed that in the presence of ultrasound; the reaction time minimizes up to 4 h as compared to mechanical stirring method (7 h). The physiochemical properties for the 2-ethylhexyl palmitate were also evaluated.

Lipase-catalyzed synthesis of propyl-phenyl acetate: a kinetic and thermodynamic study.

This study focuses on the synthesis of propyl-phenyl acetate via esterification reaction in the presence of immobilized Candida antartica lipase-B (CAL-B). In this work, the effect of relevant factors (kinetics and thermodynamic) on total percent conversion and process optimization was studied. The reaction was performed in heptane medium with 1:2 molar ratio of benzoic acid: n-propanol with 0.6% (w/v) biocatalyst loading at 40 °C to attain a maximum conversion of 96.1% within 40 min of reaction time. Effect of increase in temperature on ∆G values indicates that lipase is more promising at moderate temperature (40 °C). A second-order kinetic model was proposed to evaluate apparent kinetic constants that indicate a good agreement between the experimental and theoretical data (0.94 ≤ R2 ≤ 0.99) with high initial reaction rate (113.5 mM/min). Finally, the catalyst CAL-B was successfully reused eight times without any significant decrease in relative activity.

Biological metal organic framework (bio-MOF) of glucoamylase with enhanced stability.

The handling of conventional enzyme- metal organic framework (MOF) composites is big challenge due to their nano-sized and lightweight structure with low density. Also, conventional MOFs are derived from non-renewable petroleum feedstock which makes them inherent toxic and non-biodegradable. To overcome these difficulties, recently, green, renewable framework material composite, biological metal-organic frameworks (bio-MOFs) have intrigued as a novel class of porous materials. Here, glucoamylase was encapsulated within ZIF-8 in presence of functionalized carboxymethylcellulose (CMC) at mild aqueous conditions. The successful formation of glucoamylase bio-MOF was confirmed by Fourier transform infrared (FT-IR), X-Ray Diffraction (XRD) and scanning electron microscopy (SEM). In thermal stability, glucoamylase bio-MOF exhibited 187 % enhanced thermal stability in the temperature range of 55-75 °C as compared to native form. Further, glucoamylase bio-MOF was recycled for 5 cycles and compared their activity with traditional glucoamylase MOF. Glucoamylase bio-MOF showed significantly improved recyclability which was attributed by adhesive nature of CMC. Finally, the conformational change occurred in enzyme after immobilization was determined by FT-IR data tools.

A rapid self-assembled hybrid bio-microflowers of alpha-amylase with enhanced activity.

In conventional preparation of enzyme embedded organic-inorganic hybrid flower-like nanostructures, usually it requires three days which is time-consuming and limits their widespread applications. In this context, alpha-amylase hybrid bio-microflowers were prepared by simple, efficient and rapid method in the presence of chitosan via inotropic gelation and biomineralization approach. The hybrid bio-microflowers was synthesized within 6 h with ∼140 % enhanced catalytic activity. The prepared hybrid bio-microflowers were characterized by FT-IR, SEM, and PXRD. The hybrid bio-microflowers exhibited higher rate of reaction (Vmax) and outstanding thermo-stability (in the temperature range 55-75 °C). Further, hybrid bio-microflowers showed magnificent reusability (upto eight cycles) and long-term storage stability (for about 30 days). In the end, in starch hydrolytic study, immobilized alpha-amylase exhibited higher hydrolytic potential towards corn, wheat and potato starch as compared to free form. This designed hybrid bio-microflowers can be employed as an engineered biocatalyst in industrial applications.

Response surface methodology for the extraction of wedelolactone from Eclipta alba using aqueous two-phase extraction.

Aqueous two-phase extraction of wedelolactone from Eclipta alba was studied using the polymer-salt system. The system consisted of polyethylene glycol (PEG) as a top phase (polymer) and sodium citrate as a bottom phase (salt). Process parameters such as PEG concentration, PEG molecular weight, salt concentration, and pH have been optimized using response surface methodology (RSM) with the help of central composite design (CCD). The optimized conditions for aqueous two-phase system (ATPS), in the case of one factor at a time approach, were found as PEG 6000, PEG concentration 18% (w/v), salt concentration 16% (w/v), and pH 7; with maximum extraction yield of 6.52 mg/g. While, RSM studies showed maximum extraction yield of 6.73 mg/g with the optimized parameters as PEG 6000, PEG concentration 18% (w/v), salt concentration 17.96% (w/v), and pH 7. ATPS was found to give a 1.3 fold increase in the extraction yield of wedelolactone as compared to other conventional extraction methods.

Role of ultrasound in assisted fermentation technologies for process enhancements.

Biological molecules are widely produced by fermentation technology using bacteria, fungi or yeast. Fermentation is a biochemical process wherein the rate of bioconversion is governed by the organisms involved. The growth of the organism is mainly limited by mass transfer rates of nutrients and gases that directly affect the product formation in fermentation. Attempts have been made to enhance the growth rate and yield using mutational, recombinant strain development approach at microbial level as well as fed batch and continuous processing approach at bioprocess level in the past. The growth rate of microbes can be accelerated by increased mass transfer rates and cell wall permeability with the use of controlled low frequency ultrasound irradiation. The present review provides insights into the application of acoustic cavitation in process intensification of fermentation approaches and the role of various factors involved are highlighted with typical examples.

Facile fabrication of silver on magnetic nanocomposite (Fe3O4@Chitosan -AgNP nanocomposite) for catalytic reduction of anthropogenic pollutant and agricultural pathogens.

In this work, a novel approach was developed to synthesis advance magnetic nano-catalyst; Fe3O4@Chitosan -AgNP nanocomposite. It is made up of chitosan (fish industry-waste) doped onto the magnetic core with active silver nanoparticles on the exterior shell using NaBH4 as reductant and total soluble solids (dairy effluent-waste) as a stabilizing agent. TEM images confirm the average mean diameter of composed nanocatalyst about 8 ± 2.2 nm. SEM images, EDX spectra, and ICP-MS data confirmed the co-presence of Ag, Fe, C, and O elements with a calculated percentage weight of Ag as 8.15%. XRD patterns revealed the product was chitosan doped iron oxide with surfaced silver nanoparticles. XPS and FTIR confirm composition, elemental electronic state, and binding energy. Additionally, it is utilized as an effective solid-phase catalyst for the reduction of anthropogenic pollutant p-nitrophenol to p-aminophenol. It has a very convenient magnetic separability. ICP-Ms data for cumulative silver release shows prepared nanocatalyst remains active and stable even after recycled for more than 15 times. Also, an excellent antifungal activity was observed against the agricultural pathogens such as Colletotrichum coccodes, Aspergillus niger, and Pyricularia sp. Thus, functionalized nanostructures Fe3O4@Chitosan -AgNP magnetic nanocomposite can probably hold greater potential in catalysis and agriculture applications.

Enzyme embedded metal organic framework (enzyme-MOF): De novo approaches for immobilization.

The porous material has been considered as a potential candidate for immobilizing enzymes. Recently, metal organic framework (MOF) has been emerged as a hybrid organic inorganic material with unique intrinsic properties such as well-defined pore structure, excellent chemico-thermal stability, and extremely high surface areas which make them as a suitable scaffold for enzyme immobilization. The outstanding improvement in catalytic performance, high enzyme loading capacity, remarkable interaction between enzyme and MOF are the key features of the novel enzyme-MOF biocomposites. Amongst different immobilization approaches of enzyme-MOF composite development, de novo strategy received immense attention due to rapid, facile, mild immobilization procedure which exhibits potentially superior catalytic activity and extraordinary operational stability. This review presents a holistic insight of two different de novo strategies i.e. co-precipitation and biomineralization with state-of-art examples. Further, the recent developments in enzyme-MOF composites along with their potential features and characteristics are exploited in terms of catalytic activity, thermal/chemical stability, Michaelis-Menten kinetics, recyclability and storage stability. The advanced de novo strategies such as multi-enzyme catalytic system and magnetic enzyme-MOF are explored in the latter part of highlights.

Immobilization of proline activated lipase within metal organic framework (MOF).

The immobilization of enzyme with enhanced catalytic activity is the major challenge. In this work, we have activated the lipase in the presence of proline and successfully immobilized into zeolitic imidazolate framework (ZIF)-8 by biomineralization method. The prepared lipase-proline MOF exhibited 135% enhanced catalytic activity as compared to free counterpart. Further, it exhibited four-fold improved thermal stability with respect to native enzyme after immobilization. In Michaelis-Menten kinetic studies, Km values for lipase-proline MOF were found to be lower, whereas, it exhibited higher Vmax than lipase-MOF and free lipase. The lipase-MOF and lipase-proline MOF were showed 56% and 72% residual activity, respectively after six cycles of reuse.

Entrapment of surfactant modified lipase within zeolitic imidazolate framework (ZIF)-8.

Mostly, enzyme activity is reduced after immobilization of enzyme within MOF due to unfavourable conformational changes occurred during the immobilization procedure. In this context, lipase was activated by surfactants (in order to get a highly active enzyme) followed by encapsulation within zeolitic imidazolate framework (ZIF)-8 via one-pot facile self-assembly method. The prepared lipase-SDS ZIF-8 exhibited 250% enhanced activity compared to native form. The prepared biocomposite was characterized and analysed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM). Thermo-stability was determined for prepared lipase-SDS ZIF-8 biocomposite in the range of 50-70 °C, which showed more than two-folds enhanced stability in terms of half-life. Further, immobilized lipase retained 76% of residual activity even after six repetitive cycles and, it showed 91% residual activity after twenty days of long term storage. Finally, lipase-SDS ZIF-8 was tested for chemical stability in polar denaturing solvents which showed excellent stability as compared to free lipase.