Application of commercial and non-commercial immobilized lipases for biocatalytic production of ethyl lactate in organic solvents

Adsorption of extracellular lipase in a packed-bed reactor: an alternative immobilization approach

In light of the growing demand for novel biocatalysts and enzyme production methods, this study aimed to evaluate the potential of Aspergillus tubingensis for producing lipase under submerged culture investigating the influence of culture time and inducer treatment. Moreover, this study also investigated conditions for the immobilization of A. tubingensis lipase by physical adsorption on styrene-divinylbenzene beads (Diaion HP-20), for these conditions to be applied to an alternative immobilization system with a packed-bed reactor. Furthermore, A. tubingensis lipase and its immobilized derivative were characterized in terms of their optimal ranges of pH and temperature. A. tubingensis was shown to be a good producer of lipase, obviating the need for inducer addition. The enzyme extract had a hydrolytic activity of 23 U mL-1 and achieved better performance in the pH range of 7.5 to 9.0 and in the temperature range of 20 to 50 °C. The proposed immobilization system was effective, yielding an immobilized derivative with enhanced hydrolytic activity (35 U g-1), optimum activity over a broader pH range (5.6 to 8.4), and increased tolerance to high temperatures (40 to 60 ℃). This research represents a first step toward lipase production from A. tubingensis under a submerged culture and the development of an alternative immobilization system with a packed-bed reactor. The proposed system holds promise for saving time and resources in future industrial applications.

Biocatalysts Based on Immobilized Lipases for the Production of Fatty Acid Ethyl Esters: Enhancement of Activity through Ionic Additives and Ion Exchange Supports

Ionic additives affect the structure, activity and stability of lipases, which allow for solving common application challenges, such as preventing the formation of protein aggregates or strengthening enzyme-support binding, preventing their desorption in organic media. This work aimed to design a biocatalyst, based on lipase improved by the addition of ionic additives, applicable in the production of ethyl esters of fatty acids (EE). Industrial enzymes from Thermomyces lanuginosus (TLL), Rhizomucor miehei (RML), Candida antárctica B (CALB) and Lecitase®, immobilized in commercial supports like Lewatit®, Purolite® and Q-Sepharose®, were tested. The best combination was achieved by immobilizing lipase TLL onto Q-Sepharose® as it surpassed, in terms of %EE (70.1%), the commercial biocatalyst Novozyme® 435 (52.7%) and was similar to that of Lipozyme TL IM (71.3%). Hence, the impact of ionic additives like polymers and surfactants on both free and immobilized TLL on Q-Sepharose® was assessed. It was observed that, when immobilized, in the presence of sodium dodecyl sulfate (SDS), the TLL derivative exhibited a significantly higher activity, with a 93-fold increase (1.02 IU), compared to the free enzyme under identical conditions (0.011 IU). In fatty acids ethyl esters synthesis, Q-SDS-TLL novel derivatives achieved results similar to commercial biocatalysts using up to ~82 times less enzyme (1 mg/g). This creates an opportunity to develop biocatalysts with reduced enzyme consumption, a factor often associated with higher production costs. Such advancements would ease their integration into the biodiesel industry, fostering a greener production approach compared to conventional methods.

Sustainable Castor Bean Biodiesel Through Ricinus communis L. Lipase Extract Catalysis

The rise in oil prices, global warming, and the depletion of nonrenewable resources have led researchers to study sustainable alternatives to increasing energy demand. The autocatalysis from castor oil and castor lipases to produce biodiesel can be an excellent alternative to reduce the production costs and avoid the drawbacks of chemical transesterification. This study aimed to evaluate the catalytic activity of castor bean lipase extract (CBLE) on three vegetable oils hydrolysis, to obtain and enhance biodiesel yield by an autocatalysis from castor oil and CBLE. Furthermore, the enzymatic biodiesel physicochemical quality was analyzed. The enzymatic activity for olive oil was 76.12 U, 90.06 U for commercial castor oil, and 75.60 U in raw castor oil. The hydrolysis percentages were high at 25 °C, pH 4.5, for 4 h with 97.18% for olive oil, 98.86%, and 96.19% for commercial and raw castor oil, respectively. The CBLE catalyzed the transesterification reaction on castor oil to obtain 82.91% biodiesel yield under the selected conditions of 20% lipase loading, 1:6 oil/methanol molar ratio, and 10% buffer pH 4.5, 37 °C for 8 h. The castor biodiesel quality satisfied the ASTM-D6751 (USA) and EN-14214 (European Union) values, except for the density, viscosity, and moisture, as expected for this kind of biodiesel.

In situ purification and enrichment of fructo-oligosaccharides by fermentative treatment with Bacillus coagulans and selective catalysis using immobilized fructosyltransferase

Fructo-oligosaccharides (FOS) are prebiotic sugar substitutes that can be produced from sucrose using fructosyltransferases (FTases). However, the economic value of this process is limited by inefficient product purification and enzyme reusability. In this study, enzyme-free FOS preparations were produced by immobilizing the FTase on resin carriers. This also increased the catalytic selectivity of the enzyme. However, the crude FOS preparations still contained high concentrations of monosaccharide byproducts and residual disaccharides that must be removed because they lack prebiotic activity. A hybrid process was developed in which fed-batch fermentation was combined with the probiotic bacterium Bacillus coagulans (which selectively utilizes monosaccharides) and the simultaneous conversion of residual sucrose using the FTase to increase FOS purity. This process depleted the monosaccharides and increased the concentration of FOS to 130-170 g·L^-1. The residual sucrose was converted to FOS by the immobilized FTase, increasing the overall purity of FOS to 92.1%.

Palm Oil Decanter Cake Wastes as Alternative Nutrient Sources and Biomass Support Particles for Production of Fungal Whole-Cell Lipase and Application as Low-Cost Biocatalyst for Biodiesel Production

This is the first report on the possible use of decanter cake waste (DCW) from palm oil industry as alternative nutrient sources and biomass support particles for whole-cell lipase production under solid-state fermentation (SSF) by newly isolated fungal Aspergillus sp. MS15 and their application as a low-cost and environment-friendly biocatalyst for biodiesel production. The results found that DCW supplemented with 0.1% K2HPO4, 0.05% MgSO4·7H2O, 1% peptone and 2% urea and pH adjusted to 6.0 was optimal for whole-cell lipase production. The optimal moisture content and fermentation temperature was 60% and 37.5 °C, respectively. Environmentally friendly biodiesel production, through either esterification or transesterification using whole-cell lipase immobilized on DCW as a biocatalyst, was optimized. The optimal reaction temperature for both reactions was 37 °C. The whole-cell lipase effectively esterified oleic acid into >95% biodiesel yield through esterification under optimal water activity at 0.71 and an optimal methanol to oleic acid molar ratio of 2:1, and also effectively transesterified palm oil under optimal water activity at 0.81 and an optimal methanol to oil molar ratio of 3:1. The fuel properties of produced biodiesel are close to the international biodiesel standards. These results have shown the circular utilization of palm oil mill waste for the low-cost production of an effective biocatalyst, and may contribute greatly to the sustainability of renewable bioenergy production.

One-pot conversion of dihydroxyacetone into ethyl lactate by Zr-based catalysts

Efficient strategies for producing bio-based reagents from sustainable biomass are highly attractive for cost-effective sustainable manufacturing. In this study, a series of eco-friendly Zr-based catalysts (basic zirconium carbonate, zirconium dioxide and zirconium hydroxide) were investigated for the efficient conversion of dihydroxyacetone to ethyl lactate in a one-pot system, in which basic zirconium carbonate exhibited the best performance with 100% dihydroxyacetone conversion and 85.3% EL (ethyl lactate) yield at 140 °C, 4.0 h and 1.0 MPa N2. The improved activity of basic zirconium carbonate could be attributed to the synergistic effect among acid and base active sites. Furthermore, this low-cost catalyst shows improved thermochemical stability and recyclability under optimal conditions, where no significant decrease in activity was observed after three runs. This catalytic process could be identified as a promising alternative to produce ethyl lactate from renewable biomass and its derivatives.

Recent advancements in the synthesis of novel thermostable biocatalysts and their applications in commercially important chemoenzymatic conversion processes

Thermostable enzymes are a field of growing interest in bioremediation, pharmaceuticals, food industry etc., due to their ability to catalyze bio reactions at high temperatures. This review aims to provide an overview on extremophiles with a special focus on thermophiles and enzymes produced from extremophilic bacteria. Novel thermostable catalysts, used in producing commercially important chemicals, are discussed in this review. Various classes of enzymes produced by microbes, synthesis of thermozymes and comparison with enzymes produced at optimal conditions are critically discussed. A detailed discussion on immobilized enzymes in comparisons with free enzymes, produced by extremozymes, is included. Different parameters which affect enzyme production are also discussed. The current industrial trends along with the future of biocatalysts in the production of chemicals using efficient methods are also discussed.

Photochemical Synthesis of Lactic Acid Esters at Ambient Temperature Employing Sulfonically Fuctionalized N/W-Doped Nano-semiconductor

Appreciating the wide array of applications of lactic acid esters in the flavoring industry as well as in cosmetic and pharmaceutical industries, respectively, their clean and green synthesis gain immense importance. Therefore, traditional ester synthesis processes, involving high-temperature requirements, need to be replaced. A photochemical route has been adopted where visible light illumination was used as the major driving force to synthesize lactic acid esters. This process involves the application of sulfonically functionalized nitrogen/tungsten-doped nanotitania as photocatalysts. These functionalized catalysts efficiently and repeatedly catalyzed the esterification of lactic acid at ambient temperature. The photo-activity of these catalysts is attributed to the presence of a large number of active sulfonate sites on its surface. As per the proposed photochemical mechanism, illumination initiates the electron discharge from the conduction band, which migrates toward absorbed lactic acid through sulfonate sites forming lactic acid radical. This radical in turn attracts the alcohol molecules producing the desired ester. Reaction parameters were optimized to maximize the product yield. The economic validity of the photocatalyst was specked by repetitive experiments, and both the catalysts were found to be efficient even after five reusability cycles. The development of these catalysts can completely replace commercial ester synthesis strategies.

A green and energy-efficient photocatalytic process for the accelerated synthesis of lactic acid esters using functionalized quantum dots

Sulphonated-grafted-titania quantum dot catalyzed green and energy-efficient photochemical process for the synthesis of valuable lactic acid esters at ambient temperature.

Recent developments in enzyme immobilization technology for high-throughput processing in food industries

The demand for food and beverage markets has increased as a result of population increase and in view of health awareness. The quality of products from food processing industry has to be improved economically by incorporating greener methodologies that enhances the safety and shelf life via the enzymes application while maintaining the essential nutritional qualities. The utilization of enzymes is rendered more favorable in industrial practices via the modification of their characteristics as attested by studies on enzyme immobilization pertaining to different stages of food and beverage processing; these studies have enhanced the catalytic activity, stability of enzymes and lowered the overall cost. However, the harsh conditions of industrial processes continue to increase the propensity of enzyme destabilization thus shortening their industrial lifespan namely enzyme leaching, recoverability, uncontrollable orientation and the lack of a general procedure. Innovative studies have strived to provide new tools and materials for the development of systems offering new possibilities for industrial applications of enzymes. Herein, an effort has been made to present up-to-date developments on enzyme immobilization and current challenges in the food and beverage industries in terms of enhancing the enzyme stability.

Immobilization of Lipozyme TL 100L for methyl esterification of soybean oil deodorizer distillate

An immobilization method for binding cross-linked enzyme aggregates of Lipozyme TL 100L on macroporous resin NKA (CLEA-TLL@NKA) was developed in this study. The esterification activity of CLEA-TLL@NKA reached 6.4 U/mg. The surface structure of immobilized lipase was characterized by scanning electron microscopy. Methyl esterification reaction of soybean oil deodorizer distillate (SODD) was catalyzed by CLEA-TLL@NKA, which the conversion rate reached 98% and its activity retained over 90% after 20 batches of reaction. Compared with the commercial enzyme Lipozyme TLIM, half-life (t _1/2) of CLEA-TLL@NKA increased by 25 times and the catalytic activity increased by approximate 10 times. Thus, CLEA-TLL@NKA had high catalytic activity, good operational stability, and potential industrial application in the field of oil processing.

Immobilization of Aspergillus niger lipase onto a novel macroporous acrylic resin: Stable and recyclable biocatalysis for deacidification of high-acid soy sauce residue oil

Deacidification of high-acid soy sauce residue (SSR) oil is crucial to utilization of SSR oil. Aspergillus niger lipase (ANL) has been widely applied for such purpose while its immobilization still has large room for improvement. ANL was immobilized onto six different macroporous acrylic resins, accounting the effect of the different textural properties of resins on stability and their potential for application in enzymatic deacidification. The resin MARE with lower porosity, higher bulk density, and medium hydrophobicity, was chosen as the best carrier for the best thermostability and reusability. ANL-MARE is a promising catalyst than Novozym 40086, which not only exhibited higher deacidification activity and good thermostability, but also was continuously reused for 15 cycles and efficiently catalyzed from high-acid SSR oil into diacylglycerol-enriched oil. Therefore, immobilized ANL was a novel, low-cost and recyclable biocatalyst that could be used as a good alternative to higher-cost commercial lipases in industrial applications.

Development and economic evaluation of an eco-friendly biocatalytic synthesis of emollient esters

During the past decades the understanding and prospects of enzyme-catalysed reactions have been massively widened and there are a number of implemented large-scale enzymatic processes mainly based in the use of commercial biocatalysts. As it might happen that the same process can be successfully carried out by different commercial lipases, the election of the biocatalyst must rely on productivity and economic considerations. This work presents productiveness and direct operation cost evaluation as a key tool for the selection between two commercial lipase catalysts, the versatile but expensive Novozym^® 435 and a much more economical option, Lipozyme^® TL IM, in the synthesis of spermaceti, a mixture of emollient esters with cosmetic applications. Proving that Novozym^® 435 leads to minimum savings of 10% with respect to the cheapest immobilized derivative, biocatalyst cost does not appear to be the major contribution to the economics of the processes under study, due to their great capacity to be recovered and reused. At laboratory scale, the biggest economic investment is caused by substrates, which can be massively reduced at industrial scale by using bulk reagents. In such case, energy cost may be the major contribution to the process economy. This work proposes an optimized process ready to be scaled-up in order to accurately determine the energetic requirements of the possible industrial enzymatic synthesis.

Biocycle Fermentation Based on Lactic Acid Bacteria and Yeast for the Production of Natural Ethyl Lactate

Ethyl lactate is widely used in food and pharmaceutical industries, but the complexity of the synthesis process, in particular, involving the addition of organic solvents, hinders its application. Here, we report a natural green strategy to produce ethyl lactate by exploiting the synergistic fermentation of lactic acid bacteria and ester-producing microbes using biomass as a substrate. Interestingly, it is worth noting that the conjugate fermentation has a higher ethyl lactate yield (3.05 g/L) compared to the mixed fermentation (1.32 g/L). The ester production capacity was increased by 2.3 times. These entire processes require only the addition of biomass without introducing any organic solvent. In addition, the obtained catalytic esterification system can reuse the ester-producing microbes by simple centrifugation and maintain over seven cycles of catalysis while it retained a high activity. We firmly believe that the results of this study will provide new ideas for achieving sustainable green production of natural ethyl lactate.

Synthesis of flavor esters by a novel lipase from Aspergillus niger in a soybean-solvent system

To find a lipase for synthesis of flavor esters in food processing, a total of 35 putative lipases from Aspergillus niger F0215 were heterologously expressed and their esterification properties in crude preparations were examined. One of them, named An-lipase with the highest esterification rate (23.1%) was selected for further study. The purified An-lipase had the maximal activity at 20 °C and pH 6.5 and the specific activity of 1293 U/mg. Sixty percent of the activity was maintained in a range of temperatures of 0-30 °C and pHs of 3.0-8.5. The highest hydrolysis activity of An-lipase was towards pNPC (C8), followed by pNPB (C4) and pNPA (C2), then pNPL (C12). K _m, V _max, k _cat, and k _cat/K _m towards pNPC were 26.7 mmol/L, 129.9 mmol/(L h), 23.2 s^-1, and 0.8/mM/s, respectively. The ethyl lactate, butyl butyrate, and ethyl caprylate flavor esters were produced by esterification of the corresponding acids with conversion efficiencies of 15.8, 37.5, and 24.7%, respectively, in a soybean-oil-based solvent system. In conclusion, An lipase identified in this study significantly mediated synthesis of predominant flavor esters (ethyl lactate, butyl butyrate, and ethyl caprylate) in a soybean-oil-lacking other toxic organic solvents, which has potential application in food industries.

Novozym 435: the “perfect” lipase immobilized biocatalyst?

Novozym 435 (N435) is a commercially available immobilized lipase produced by Novozymes with its advantages and drawbacks.