Pilot-scale development of core-shell polymer supports for the immobilization of recombinant lipase B from Candida antarctica and their application in the production of ethyl esters from residual fatty acids

Unveiling six novel CALB-like lipases using genome-centric and patent-driven prospection

Lipases present biotechnological applications in various industrial sectors due to their ability to perform multiple biochemical reactions. However, the high cost sometimes discourages their potential uses, besides the extensive number of patents involving them. One of the most utilized and researched lipases is Candida antarctica lipase B (CALB), known for its versatility, encompassing enantioselectivity, thermostability, and a wide range of substrates. Therefore, finding new CALB-like lipases is an interesting strategy to enable the implementation of biocatalysts, especially if intellectual property analysis is included. The present study identified and produced six CALB-like enzymes without patent protection, with differences in pocket amino acids and substrate specificity. We conducted genomic searches in almost 7000 Fungal genomes, identifying over 1500 unique CALB homolog candidates. The phylogenetic and intellectual property analysis filtered those results into a few sequences without protection that were very similar to CALB. One cloned lipase had a lower hydrophobicity at the pocket entrance and preferred the C4 p-nitrophenyl ester as substrate. Another had a wider opening and more polar pocket, showing no preference. These results identified new patent-free lipases with conserved essential catalytic elements and diverse substrate specificity due to variations in the catalytic pocket. These enzymes can be the starting point for biocatalyst innovation with potential applications in diverse biotechnological areas.

Has the time finally come for green oleochemicals and biodiesel production using large-scale enzyme technologies? Current status and new developments

With the growth of the chemical industry over the last decade, the need for cheaper (and more environmentally friendly) alternatives to petrochemicals of ever-increasing cost has grown steadily. Oleochemicals and biodiesel (OC/BD) are considered as green alternatives to petroleum derivatives, because they come from renewable oils and fats. OC/BD are currently produced by the traditional energy intensive chemical catalyzed methods, which have several economic and environmental drawbacks. For these reasons, the enzymatic production of OC/BD has attracted a growing attention for their greener pathway with respect to the chemically catalyzed processes. Lipase-catalyzed processes have a low energy requirement, since reactions are performed under atmospheric pressure and mild temperature and without the creation of side reactions. Furthermore, utilization of enzyme catalysts offers many advantages such as reducing the initial capital investment due to simplified downstream processing steps. Despite all the previous advantages, however, the high cost of lipases restricted their large-scale utilization. In the past decade, efforts have been made to reduce the cost of the enzymatic-catalyzed synthesis of OC/BD. However, most previous studies have studied only the technical feasibility of the lipase-catalyzed reactions and overlocked the economic viability. This review critically discusses the factors affecting the promotion of the economic feasibility of the enzymatic processes from the lab to large scale. These include reactor configuration, type of feedstock, conditions optimization, immobilization, lipase-producing microorganisms, and substrate diversification. In addition, this review reports the recent advances in lipase-catalyzed production of fatty acids, fatty esters, monoglycerides, and biodiesel in the lab as well as in the large-scales. To the best of authors' knowledge, this is the first review article reports the recent global progress achieved in both lab- and large-scale for the enzymatic production of OC/BD.

Technical–Economic Assessment—The Missing Piece for Increasing the Attractiveness of Applied Biocatalysis in Ester Syntheses?

Although the current literature describes significant advances in biocatalytic ester syntheses, few industrial plants worldwide are currently producing esters using biocatalysts. Green and sustainable esters can be obtained via a biocatalytic route, including some operational advantages over conventional syntheses. An analysis of the literature revealed that most articles neglect or describe the economic issues generically, without quantitative information. Scaling-up studies are also scarce in this field. The main disadvantage of biocatalysis using immobilized lipases—their cost—has not been studied at the same level of depth as other technical aspects. This gap in the literature is less intense in enzymatic biodiesel production studies and, despite the lack of a strict correlation, enzymatic biodiesel commercial plants are relatively more common. Preliminary techno-economic assessments are crucial to identify and circumvent the economic drawbacks of biocatalytic ester syntheses, opening the way to broader application of this technology in a large-scale context.

Mineralization of Lipase from Thermomyces lanuginosus Immobilized on Methacrylate Beads Bearing Octadecyl Groups to Improve Enzyme Features

Lipase from Thermomyces lanuginosus (TLL) has been immobilized on Purolite Lifetech® ECR8806F (viz. methacrylate macroporous resin containing octadecyl groups, designated as Purolite C18-TLL), and the enzyme performance has been compared to that of the enzyme immobilized on octyl-agarose, designated as agarose C8-TLL. The hydrolytic activity versus p-nitrophenol butyrate decreased significantly, and to a lower extent versus S-methyl mandelate (more than twofold), while versus triacetin and R-methyl mandelate, the enzyme activity was higher for the biocatalyst prepared using Purolite C18 (up to almost five-fold). Regarding the enzyme stability, Purolite C18-TLL was significantly more stable than the agarose C8-TLL. Next, the biocatalysts were mineralized using zinc, copper or cobalt phosphates. Mineralization increased the hydrolytic activity of Purolite C18-TLL versus triacetin and R-methyl mandelate, while this activity decreased very significantly versus the S-isomer, while the effects using agarose C8-TLL were more diverse (hydrolytic activity increase or decrease was dependent on the metal and substrate). The zinc salt treatment increased the stability of both biocatalysts, but with a lower impact for Purolite C18-TLL than for agarose-C8-TLL. On the contrary, the copper and cobalt salt treatments decreased enzyme stability, but more intensively using Purolite C18-TLL. The results show that even using enzymes immobilized following the same strategy, the differences in the enzyme conformation cause mineralization to have diverse effects on enzyme stability, hydrolytic activity, and specificity.

Comparative performance and reusability studies of lipases on syntheses of octyl esters with an economic approach

A suitable immobilized lipase for esters syntheses should be selected considering not only its cost. We evaluated five biocatalysts in syntheses of octyl caprylate, octyl caprate, and octyl laurate, in which conversions higher than 90% were achieved. Novozym^® 435 and non-commercial preparations (including a dry fermented solid) were selected for short-term octyl laurate syntheses using different biocatalysts loadings. By increasing the biocatalyst's loading the lipase's reusability also raised, but without strict proportionality, which resulted in a convergence between the lowest biocatalyst loading and the lowest cost per batch. The use of a dry fermented solid was cost-effective, even using loadings as high as 20.0% wt/wt due to its low obtaining cost, although exhibiting low productiveness. The combination of biocatalyst's cost, esterification activity, stability, and reusability represents proper criteria for the choice. This kind of assessment may help to establish quantitative goals to improve or to develop new biocatalysts.

Robust nanocarriers to engineer nanobiocatalysts for bioprocessing applications

The synergistic integration of bio-catalysis engineering with nanostructured materials, as unique multifunctional carrier matrices, has emerged as a new interface of nanobiocatalysis (NBC). NBC is an emerging innovation that offers significant considerations to expand the designing and fabrication of robust catalysts at the nanoscale with improved catalytic characteristics for multipurpose bioprocessing applications. In addition, nanostructured materials with unique structural, physical, chemical, and functional entities have manifested significant contributions in mimicking the enzyme microenvironment. A fine-tuned enzyme microenvironment with an added-value of NBC offers chemo- regio- and stereo- selectivities and specificities. Furthermore, NBC is growing rapidly and will become a powerful norm in bio-catalysis with much controlled features, such as selectivity, specificity, stability, resistivity, induce activity, reaction efficacy, multi-usability, improved mass transfer efficiency, high catalytic turnover, optimal yield, ease in recovery, and cost-effectiveness. Considering the above critics and unique structural, physicochemical, and functional attributes, herein, we present and discuss advances in NBC and its bioprocessing applications in different fields. Briefly, this review is focused on four parts, i.e., (1) NBC as a drive towards applied nanobiocatalysts (as an introduction with opportunities), (2) promising nanocarriers to develop nanobiocatalysts, (3) applications in the fields of biotransformation, biofuel production, carbohydrate hydrolysis, bio-/nanosensing, detergent formulations, and extraction and purification of value-added compounds, and (4) current challenges, concluding remarks, and future trends.

Effect of Concentrated Salts Solutions on the Stability of Immobilized Enzymes: Influence of Inactivation Conditions and Immobilization Protocol

This paper aims to investigate the effects of some salts (NaCl, (NH₄)₂SO₄ and Na₂SO₄) at pH 5.0, 7.0 and 9.0 on the stability of 13 different immobilized enzymes: five lipases, three proteases, two glycosidases, and one laccase, penicillin G acylase and catalase. The enzymes were immobilized to prevent their aggregation. Lipases were immobilized via interfacial activation on octyl agarose or on glutaraldehyde-amino agarose beads, proteases on glyoxyl agarose or glutaraldehyde-amino agarose beads. The use of high concentrations of salts usually has some effects on enzyme stability, but the intensity and nature of these effects depends on the inactivation pH, nature and concentration of the salt, enzyme and immobilization protocol. The same salt can be a stabilizing or a destabilizing agent for a specific enzyme depending on its concentration, inactivation pH and immobilization protocol. Using lipases, (NH₄)₂SO₄ generally permits the highest stabilities (although this is not a universal rule), but using the other enzymes this salt is in many instances a destabilizing agent. At pH 9.0, it is more likely to find a salt destabilizing effect than at pH 7.0. Results confirm the difficulty of foreseeing the effect of high concentrations of salts in a specific immobilized enzyme.

Effects of Enzyme Loading and Immobilization Conditions on the Catalytic Features of Lipase From Pseudomonas fluorescens Immobilized on Octyl-Agarose Beads

The lipase from Pseudomonas fluorescens (PFL) has been immobilized on octyl-agarose beads under 16 different conditions (varying pH, ionic strength, buffer, adding some additives) at two different loadings, 1 and 60 mg of enzyme/g of support with the objective of check if this can alter the biocatalyst features. The activity of the biocatalysts versus p-nitrophenyl butyrate and triacetin and their thermal stability were studied. The different immobilization conditions produced biocatalysts with very different features. Considering the extreme cases, using 1 mg/g preparations, PFL stability changed more than fourfolds, while their activities versus pNPB or triacetin varied a 50-60%. Curiously, PFL specific activity versus triacetin was higher using highly enzyme loaded biocatalysts than using lowly loaded biocatalysts (even by a twofold factor). Moreover, stability of the highly loaded preparations was higher than that of the lowly loaded preparations, in many instances even when using 5°C higher temperatures (e.g., immobilized in the presence of calcium, the highly loaded biocatalysts maintained after 24 h at 75°c a 85% of the initial activity, while the lowly loaded preparation maintained only 27% at 70°C). Using the highly loaded preparations, activity of the different biocatalysts versus pNPB varied almost 1.7-folds and versus triacetin 1.9-folds. In this instance, the changes in stability caused by the immobilization conditions were much more significant, some preparations were almost fully inactivated under conditions where the most stable one maintained more than 80% of the initial activity. Results suggested that immobilization conditions greatly affected the properties of the immobilized PFL, partially by individual molecule different conformation (observed using lowly loaded preparations) but much more relevantly using highly loaded preparations, very likely by altering some enzyme-enzyme intermolecular interactions. There is not an optimal biocatalyst considering all parameters. That way, preparation of biocatalysts using this support may be a powerful tool to tune enzyme features, if carefully controlled.

Immobilisation of lipase enzyme onto bacterial magnetosomes for stain removal

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Lipase was immobilized on magnetosome via glutaraldehyde, confirmed in FTIR and SEM.

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Release of p-nitro phenol confirmed the enzyme activity of immobilize lipase (88 %).

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The optimal pH (7) and temperature (40 °C) was standardised for activity.

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The immobilized lipase stored at 4 °C retained higher activity (87 %) than free lipase after 30 days.

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Immobilized lipase removed vegetable oil stain, better cleaning efficiency than free lipase.

Lipase was immobilized onto bacterial magnetosomes using glutaraldehyde cross-linking and confirmed by Fourier transform infrared spectrometry (FT-IR) and Scanning electron microscopy (SEM). Enzyme activity of immobilised lipase as well as free lipase was estimated by the release of p-nitro phenol due to the hydrolysis of p-nitro phenyl acetate (pNPA). The immobilisation yield of lipase onto magnetosome was found to be 88 %. The optimal pH (7) and temperature (40 °C) for activity was standardised and found to be similar to free lipase. The stored immobilized lipase maintained higher activity even after 30 days at a temperature of 4 °C whereas compared to free lipase. Immobilized lipase found to have removed vegetable oil stain and showed higher cleaning efficiency when compared to free lipase. The results suggest that bacterial magnetosome displays great potential as a support material for the immobilization of industrial enzymes such as lipase.

Novozym 435: the “perfect” lipase immobilized biocatalyst?

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

Evaluation of Strategies to Produce Highly Porous Cross-Linked Aggregates of Porcine Pancreas Lipase with Magnetic Properties

The preparation of highly porous magnetic crosslinked aggregates (pm-CLEA) of porcine pancreas lipase (PPL) is reported. Some strategies to improve the volumetric activity of the immobilized biocatalyst were evaluated, such as treatment of PPL with enzyme surface-modifying agents (polyethyleneimine or dodecyl aldehyde), co-aggregation with protein co-feeders (bovine serum albumin and/or soy protein), use of silica magnetic nanoparticles functionalized with amino groups (SMNPs) as separation aid, and starch as pore-making agent. The combination of enzyme surface modification with dodecyl aldehyde, co-aggregation with SMNPs and soy protein, in the presence of 0.8% starch (followed by hydrolysis of the starch with α-amylase), yielded CLEAs expressing high activity (immobilization yield around 100% and recovered activity around 80%), high effectiveness factor (approximately 65% of the equivalent free enzyme activity) and high stability at 40 °C and pH 8.0, i.e., PPL CLEAs co-aggregated with SMNPs/bovine serum albumin or SMNPs/soy protein retained 80% and 50% activity after 10 h incubation, respectively, while free PPL was fully inactivated after 2 h. Besides, highly porous magnetic CLEAs co-aggregated with soy protein and magnetic nanoparticles (pm-SP-CLEAs) showed good performance and reusability in the hydrolysis of tributyrin for five 4h-batches.