A high-detergent-performance, cold-adapted lipase from Pseudomonas stutzeri PS59 suitable for detergent formulation

Insights into the molecular mechanisms of lipid transformation in sturgeon fillets: Interplay between specific spoilage and dominant bacteria

This study investigates spoilage bacteria's impact on lipid metabolism in sturgeon fillets using UHPLC-Q-Orbitrap-MS/MS-based untargeted lipidomic analysis. A total of 4041 lipid molecules across five classes and 42 subclasses were identified, including glycerophospholipids (GPs, 50.88%), glycerolipids (GLs, 36.08%), sphingolipids (SPs, 10.47%), fatty acyls (FAs, 2.45%), and sterol lipids (STs, 0.12%). Aeromonas sobria, a specific spoilage bacterium, reduced GPs and FAs while increasing GLs, SPs, and STs via extracellular lipases and esterases. Acinetobacter albensis, the dominant bacterium, mainly elevated SPs and FAs. Their interaction promoted lipid metabolism and oxidation while producing volatile organic compounds (VOCs). Ethyl isobutyrate, ethyl propionate, isobutyl formate, pentan-2-one, propan-2-one, 2-butanone, 3-methyl-3-buten-1-ol, and dimethyl sulfide were mainly associated with Acinetobacter albensis, while 1-hexanol, 1-pentanol, 1-penten-3-ol, 1-hydroxypropan-2-one, 3-methyl-1-butanol, 2-methylbutanal, 3-hydroxy-2-butanone, and propionaldehyde were mainly related to Aeromonas sobria. This work unveils the mechanism of lipid transformation in sturgeon fillets during refrigerated storage, offering insights for aquatic products quality control.

Expression of microbial lipase in filamentous fungus Aspergillus niger: a review

Lipase has high economic importance and is widely used in biodiesel, food, detergents, cosmetics, and pharmaceutical industries. The rapid development of synthetic biology and system biology has not only paved the way for comprehensively understanding the efficient operation mechanism of Aspergillus niger cell factories but also introduced a new technological system for creating and optimizing high-efficiency A. niger cell factories. In this review, all relevant data on microbial lipase enzyme sources and general properties are gathered and updated. The relationship between A. niger strain morphology and protein production is discussed. The safety of A. niger strain is investigated to ensure product safety. The biotechnologies and factors influencing lipase expression in A. niger are summarized. This review focuses on various strategies to improve lipase expression in A. niger. The summary of these methods and the application of the gene editing technology CRISPR/Cas9 system can further improve the efficiency of constructing the engineered lipase-producing A. niger.

A lipase from Lacticaseibacillus rhamnosus IDCC 3201 with thermostability and pH resistance for use as a detergent additive

Lipases are important biocatalysts and ubiquitous in plants, animals, and microorganisms. The high growth rates of microorganisms with low production costs have enabled the wide application of microbial lipases in detergent, food, and cosmetic industries. Herein, a novel lipase from Lacticaseibacillus rhamnosus IDCC 3201 (Lac-Rh) was isolated and its activity analyzed under a range of reaction conditions to evaluate its potential industrial application. The isolated Lac-Rh showed a molecular weight of 24 kDa and a maximum activity of 3438.5 ± 1.8 U/mg protein at 60 °C and pH 8. Additionally, Lac-Rh retained activity in alkaline conditions and in 10% v/v concentrations of organic solvents, including glycerol and acetone. Interestingly, after pre-incubation in the presence of multiple commercial detergents, Lac-Rh maintained over 80% of its activity and the stains from cotton were successfully removed under a simulated laundry  setting. Overall, the purified lipase from L. rhamnosus IDCC 3201 has potential for use as a detergent in industrial applications. KEY POINTS: • A novel lipase (Lac-Rh) was isolated from Lacticaseibacillus rhamnosus IDCC 3201 • Purified Lac-Rh exhibited its highest activity at a temperature of 60 °C and a pH of 8, respectively • Lac-Rh remains stable in commercial laundry detergent and enhances washing performance.

Structure-directed bioengineering the lid1 of cold-adapted Pseudomonas sp. TB11 esterase to boost catalytic capacity

Structure-guided bioengineering enzymes has been an efficient strategy to obtain biocatalyst with desirable properties. In this study, the cold-adapted esterase from Pseudomonas sp. (CPE) was optimized through bioinformatic-based structured-guided bioengineering on lid1 region. Substitutions of non-conserved Q55 led to noticeable increase in hydrolysis without sacrificing enzyme thermostability, activating effects of Ca2+ and organic solvents. Compared to the wild type, both of Q55V and Q55N among the constructed variants exhibited about a 2.0-fold and 6.5-fold higher hydrolytic activity toward short-chain and long-chain substrates, respectively. In contrast, lid swapping with the lid of Thermomyces lanuginosus lipase reduced the activity and thermostability of CPE. Catalytic kinetics revealed that substitution of Q55 with Y, V, N and R enhanced the substrate affinity of CPE. Hydrolysis by Q55V remarkedly enriched the characteristic flavor components of single cream. The study sheds light on structure-guided bioengineering of lid tailoring cold-adapted esterases with desired catalytic performance to meet the demand from biotechnological applications.

Cold adapted Pseudomonas: ecology to biotechnology

The cold adapted microorganisms, psychrophiles/psychrotolerants, go through several modifications at cellular and biochemical levels to alleviate the influence of low temperature stress conditions. The low temperature environments depend on these cold adapted microorganisms for various ecological processes. The ability of the microorganisms to function in cold environments depends on the strategies directly associated with cell metabolism, physicochemical constrains, and stress factors. Pseudomonas is one among such group of microorganisms which is predominant in cold environments with a wide range of ecological and biotechnological applications. Bioformulations of Pseudomonas spp., possessing plant growth promotion and biocontrol abilities for application under low temperature environments, are well documented. Further, recent advances in high throughput sequencing provide essential information regarding the prevalence of Pseudomonas in rhizospheres and their role in plant health. Cold adapted species of Pseudomonas are also getting recognition for their potential in biodegradation and bioremediation of environmental contaminants. Production of enzymes and bioactive compounds (primarily as an adaptation mechanism) gives way to their applications in various industries. Exopolysaccharides and various biotechnologically important enzymes, produced by cold adapted species of Pseudomonas, are making their way in food, textiles, and pharmaceuticals. The present review, therefore, aims to summarize the functional versatility of Pseudomonas with particular reference to its peculiarities along with the ecological and biotechnological applications.

Mining of key genes for cold adaptation from Pseudomonas fragi D12 and analysis of its cold-adaptation mechanism

The psychrotroph Pseudomonas fragi D12, which grew strongly under low temperatures, was screened from tundra soil collected from the permanent alpine zone on Changbai Mountain. To mine the genes critical for cold tolerance and to investigate the cold-adaptation mechanism, whole-genome sequencing, comparative genomic analysis, and transcriptome analysis were performed with P. fragi. A total of 124 potential cold adaptation genes were identified, including nineteen unique cold-adaptive genes were detected in the genome of P. fragi D12. Three unique genes associated with pili protein were significantly upregulated at different degrees of low temperature, which may be the key to the strong low-temperature adaptability of P. fragi D12. Meanwhile, we were pleasantly surprised to find that Pseudomonas fragi D12 exhibited different cold-adaptation mechanisms under different temperature changes. When the temperature declined from 30°C to 15°C, the response included maintenance of the fluidity of cell membranes, increased production of extracellular polymers, elevation in the content of compatibility solutes, and reduction in the content of reactive oxygen species, thereby providing a stable metabolic environment. When the temperature decreased from 15°C to 4°C, the response mainly included increases in the expression of molecular chaperones and transcription factors, enabling the bacteria to restore normal transcription and translation. The response mechanism of P. fragi D12 to low-temperature exposure is discussed. The results provide new ideas for the cold-adaptation mechanism of cold-tolerant microorganisms.

Characterization of Sphingobacterium sp. Ab3 Lipase and Its Coexpression with LEA Peptides

Sphingobacterium sp. is a yellowish Gram-negative bacterium that is usually characterized by high concentrations of sphingophospholipids as lipid components. As microbial enzymes have been in high demand in industrial fields in the past few decades, this study hopes to provide significant information on lipase activities of Sphingobacterium sp., since limited studies have been conducted on the Sphingobacterium sp. lipase. A microbe from one collected Artic soil sample, ARC4, was identified as psychrotolerant Sphingobacterium sp., and it could grow in temperatures ranging from 0°C to 24°C. The expression of Sphingobacterium sp. lipase was successfully performed through an efficient approach of utilizing mutated group 3 late embryogenesis abundant (G3LEA) proteins developed from Polypedilum vanderplanki. Purified enzyme was characterized using a few parameters, such as temperature, pH, metal ion cofactors, organic solvents, and detergents. The expressed enzyme is reported to be cold adapted and has the capability to work efficiently under neutral pH (pH 5.0 to 7.0), cofactors like Na+ ion, and the water-like solvent methanol. Addition of nonionic detergents greatly enhanced the activity of purified enzyme. IMPORTANCE The mechanism of action of LEA proteins has remained unknown to many; in this study we reveal their presence and improved protein expression due to the molecular shielding effect reported by others. This paper should be regarded as a useful example of using such proteins to influence an existing expression system to produce difficult-to-express proteins.

An overview on the conversion of glycerol to value-added industrial products via chemical and biochemical routes

Glycerol is a common by-product of industrial biodiesel syntheses. Due to its properties, availability, and versatility, residual glycerol can be used as a raw material in the production of high value-added industrial inputs and outputs. In particular, products like hydrogen, propylene glycol, acrolein, epichlorohydrin, dioxalane and dioxane, glycerol carbonate, n-butanol, citric acid, ethanol, butanol, propionic acid, (mono-, di-, and triacylglycerols), cynamoil esters, glycerol acetate, benzoic acid, and other applications. In this context, the present study presents a critical evaluation of the innovative technologies based on the use of residual glycerol in different industries, including the pharmaceutical, textile, food, cosmetic, and energy sectors. Chemical and biochemical catalysts in the transformation of residual glycerol are explored, along with the factors to be considered regarding the choice of catalyst route used in the conversion process, aiming at improving the production of these industrial products.

Structural and functional adaptation in extremophilic microbial α-amylases

Maintaining stable native conformation of a protein under a given ecological condition is the prerequisite for survival of organisms. Extremophilic bacteria and archaea have evolved to adapt under extreme conditions of temperature, pH, salt, and pressure. Molecular adaptations of proteins under these conditions are essential for their survival. These organisms have the capability to maintain stable, native conformations of proteins under extreme conditions. The enzymes produced by the extremophiles are also known as extremozyme, which are used in several industries. Stability and functionality of extremozymes under varying temperature, pH, and solvent conditions are the most desirable requirement of industry. α-Amylase is one of the most important enzymes used in food, pharmaceutical, textile, and detergent industries. This enzyme is produced by diverse microorganisms including various extremophiles. Therefore, understanding its stability is important from fundamental as well as an applied point of view. Each class of extremophiles has a distinctive set of dominant non-covalent interactions which are important for their stability. Static information obtained by comparative analysis of amino acid sequence and atomic resolution structure provides information on the prevalence of particular amino acids or a group of non-covalent interactions. Protein folding studies give the information about thermodynamic and kinetic stability in order to understand dynamic aspect of molecular adaptations. In this review, we have summarized information on amino acid sequence, structure, stability, and adaptability of α-amylases from different classes of extremophiles.

Identification of industrial detergent enzymes by SDS-PAGE and MALDI-TOF mass spectrometry

An efficient method was proposed for routine analysis of the most widely used detergent enzymes.

A Purified Alkaline and Detergent-Tolerant Lipase from Aspergillus fumigatus with Potential Application in Removal of Mustard Oil Stains from Cotton Fabric

In the present study, the lipase from Aspergillus fumigatus was purified which was found to be stable to commercial detergents and oxidising agents. A purification fold of 6.96 and yield of 11.03% were achieved when the enzyme was purified using Octyl Sepharose column chromatography. In presence of various oxidizing agents, the highest activity of lipase was 15.56 U/mg with hydrogen peroxide. Among various surfactants used, the maximum activity exhibited by lipase was with Tween 80. While studying the effect of various detergents, the highest activity of 9.3 U/mg was achieved with "Vanish" detergent. Wash performance was studied with various detergents out of which "Vanish" showed highest oil removal of 79%. Lipase from Aspergillus fumigatus possessed better stability with various surfactants and oxidizing agents. The results of this study have shown that the lipase from Aspergillus fumigatus along with detergent "Vanish" (0.7%) under optimized conditions (5 μg/ml lipase, 40°C wash temperature and 40 min wash duration) improved oil removal from cotton fabric stained with mustard oil by 84%.

Identification and characterization of extracellular enzymes secreted by Aspergillus spp. involved in lipolysis and lipid-antioxidation during katsuobushi fermentation and ripening

A mild-flavored soup stock made from katsuobushi is an important element of traditional Japanese cuisine and is the basic seasoning responsible for the taste. Fermented and ripened katsuobushi, known as karebushi, is manufactured by simmering skipjack tuna that is then smoke-dried, fermented, and ripened in a repeated molding process by five dominant Aspergillus species. Here, our aim was to characterize and identify the lipolytic enzymes secreted by the dominant Aspergillus species, especially A. chevalieri and A. pseudoglaucus, which are involved in hydrolyzing lipids during the molding process. The crude enzyme preparations from the five Aspergillus spp. cultivated on katsuobushi solid medium hydrolyzed triglycerides in fish oil, and more saturated and unsaturated fatty acids (C16:0, C16:1, C18:0, C18:1) were produced than major polyunsaturated fatty acids (C20:5, C22:6). On the basis of ion exchange chromatograms, the composition of the lipolytic enzymes was different in the five species. There was at least one active fraction with high hydrolytic activity toward fish oil in four of the Aspergillus spp., but not A. sydowii; the lipolytic enzyme secreted by A. sydowii had quite high activity toward the artificial substrate p-nitrophenyl butyrate, but low activity toward the natural oil. The lipolytic fractions from A. chevalieri and A. pseudoglaucus were further purified by hydrophobic interaction chromatography then gel-filtration chromatography; LC-MS-MS Mascot analysis identified a variety of lipolytic enzymes, including cutinase, esterase, phospholipase, and carboxyl esterase in the lipolytic fractions from these species. The identified enzymes had 30%-70% identity to previously reported or manually annotated lipases or esterases from taxa other than Aspergillus. The different lipolytic enzymes likely acted on triglycerides in the katsuobushi fish oil. Furthermore, catalase B and Cu/Zn superoxide dismutase, which limit oxidative damage of lipids, were also identified. These antioxidant enzymes may prevent lipid oxidation and rancidity as the lipolytic enzymes hydrolyze lipids during the long fermentation and ripening process. Umami and richness tastes tended to increase in extracts from culture of protease- and peptidase-producing A. sydowii. Our results will aid in the selection and application of desirable strains of Aspergillus species as starter cultures to improve the storage and quality of fermented and ripened karebushi.

Cold Active Lipases: Biocatalytic Tools for Greener Technology

Lipases are enzymes that catalyze the ester bond hydrolysis in triglycerides with the release of fatty acids, mono- and diglycerides, and glycerol. The microbial lipases account for $400 million market size in 2017 and it is expected to reach $590 million by 2023. Many biotechnological processes are expedited at high temperatures and hence much research is dealt with thermostable enzymes. Cold active lipases are now gaining importance in the detergent, synthesis of chiral intermediates and frail/fragile compounds, and food and pharmaceutical industries. In addition, they consume less energy since they are active at low temperatures. These cold active lipases have not been commercially exploited so far compared to mesophilic and thermophilc lipases. Cold active lipases are distributed in microbes found at low temperatures. Only a few microbes were studied for the production of these enzymes. These cold-adapted enzymes show increased flexibility of their structures in response to freezing effect of the cold habitats. This review presents an update on cold-active lipases from microbial sources along with some structural features justifying high enzyme activity at low temperature. In addition, recent achievements on their use in various industries will also be discussed.

Purification and characterization of a novel extracellular, alkaline, thermoactive, and detergent-compatible lipase from Aeromonas caviae LipT51 for application in detergent industry

Lipase producer bacterium isolated from Erzurum was identified as Aeromonas caviae LipT51 (GenBank ID: MN818567.1) by 16S rDNA sequencing and conventional methods. Extracellular lipase was purified by ammonium sulphate precipitation, centrifugal filtration, and anion-exchange chromatography resulting in 6.1-fold purification with 28% final yield. Molecular weight was 31.6 kDa on SDS-PAGE. Lipase was stable over a broad range of pH (6-11) and temperature (25-70 °C), and showed optimum activity at pH 9 and 60 °C. Km and Vmax for pNPP hydrolysis were 0.88 mM and 34.2 U/mg protein, respectively. Ba²⁺, Ca²⁺, Co²⁺, Cu²⁺, Fe³⁺, and Mg²⁺ increased activity, while Mn²⁺, Mo²⁺, Ni²⁺, Zn²⁺, and other additives partially decreased. Activity and stability increased with laundry detergent and slightly decreased with handwash and dishwashing detergents. Alkaline and thermostable lipase from newly isolated A. caviae has been shown for the first time to be remarkably compatible with laundry detergent and improve washing performance by enhanced oil-stain removal.

A Broad Temperature Active Lipase Purified From a Psychrotrophic Bacterium of Sikkim Himalaya With Potential Application in Detergent Formulation

Bacterial lipases with activity spanning over a broad temperature and substrate range have several industrial applications. An efficient enzyme-producing bacterium Chryseobacterium polytrichastri ERMR1:04, previously reported from Sikkim Himalaya, was explored for purification and characterization of cold-adapted lipase. Optimum lipase production was observed in 1% (v/v) rice bran oil, pH 7 at 20°C. Size exclusion and hydrophobic interaction chromatography purified the enzyme up to 21.3-fold predicting it to be a hexameric protein of 250 kDa, with 39.8 kDa monomeric unit. MALDI-TOF-MS analysis of the purified lipase showed maximum similarity with alpha/beta hydrolase (lipase superfamily). Biochemical characterization of the purified enzyme revealed optimum pH (8.0), temperature (37°C) and activity over a temperature range of 5–65°C. The tested metals (except Cu²⁺ and Fe²⁺) enhanced the enzyme activity and it was tolerant to 5% (v/v) methanol and isopropanol. The Km and Vmax values were determined as 0.104 mM and 3.58 U/mg, respectively for p-nitrophenyl palmitate. Bioinformatics analysis also supported in vitro findings by predicting enzyme's broad temperature and substrate specificity. The compatibility of the purified lipase with regular commercial detergents, coupled with its versatile temperature and substrate range, renders the given enzyme a promising biocatalyst for potential detergent formulations.

Current prospective in using cold-active enzymes as eco-friendly detergent additive

Advanced developments in the field of enzyme technology have increased the use of enzymes in industrial applications, especially in detergents. Enzymes as detergent additives have been extensively studied and the demand is considerably increasing due to its distinct properties and potential applications. Enzymes from microorganisms colonized at various geographical locations ranging from extreme hot to cold are explored for compatibility studies as detergent additives. Especially psychrophiles growing at cold conditions have cold-active enzymes with high catalytic activity and their stability under extreme conditions makes it as an appropriate eco-friendly and cost-effective additive in detergents. Adequate number of reports are available on cold-active enzymes such as proteases, lipases, amylases, and cellulases with high efficiency and exceptional features. These enzymes with increased thermostability and alkaline stability have become the premier choice as detergent additives. Modern approaches in genomics and proteomics paved the way to understand the compatibility of cold-active enzymes as detergent additives in broader dimensions. The molecular techniques such as gene coding, amino acid sequencing, and protein engineering studies helped to solve the mysteries related to alkaline stability of these enzymes and their chemical compatibility with oxidizing agents. The present review provides an overview of cold-active enzymes used as detergent additives and molecular approaches that resulted in development of these enzymes as commercial hit in detergent industries. The scope and challenges in using cold-active enzymes as eco-friendly and sustainable detergent additive are also discussed.

Production, characterization and application of thermostable, alkaline α-amylase (AA11) from Bacillus cereus strain SP-CH11 isolated from Chilika Lake

An alkaliphile bacterial strain designated as CH11 was isolated from the sediments of Chilika Lake, Odisha. The isolate showed stupendous growth and production of α-amylase at pH 10.0. Through 16S rRNA gene based molecular technique this isolate was identified as Bacillus cereus strain SP-CH11 having GenBank Accession No. KT992791. Homogenous ~55 kDa extracellular α-amylase was extracted with 241.304, 26.26 and 3.2-fold acceleration in specific activity, purification fold and yield respectively. The alkaline α-amylase AA11 was further characterized. At pH 9.0 the purified enzyme AA11 was highly stable while retaining 88-100% functional viability at temperature range from 35 to 65 °C, confirming its thermostability nature. It showed stability with powdered and liquid detergents at 7 mg/mL and 100-fold dilutions respectively. AA11 efficiently removed the starch stain from cotton fabrics. The findings of this study indicate that the isolate CH11 is a source of novel alkaline α-amylase that has promising application in food and detergent industries.

Production optimization, characterization, and covalent immobilization of a thermophilic Serratia rubidaea lipase isolated from an Algerian oil waste

A new thermophilic non-induced lipase producer named Serratia rubidaea strain Nehal-mou was isolated from oil waste in Tissemsilat, Algeria. The most influential lipase production parameters were screened by the Plackett-Burman design for enhancing enzyme yield. An optimum condition of a 1.5% of glucose, a 0.01% of potassium, and a 0.025% of manganese contents resulted in a 41.13 U/mL. This yield was 6.29 times higher than the one achieved before the application of the Box-Behnken Design. Lipase activity showed a high organic solvent tolerance following its exposure to hexane, ethanol, methanol, and acetone. Lipase was also perfectly stable in the presence of 10 mM Fe²⁺, K⁺, and Na⁺ ions with more than 75% of the retaining activity. The enzyme half-life times were 22 h, 90 min, and 25 min at 50, 60, and 70 °C respectively. Polyvinyl alcohol (PVA)/boric acid/Starch/CaCO₃ were utilized as a carrier for lipase covalent immobilization in order to be used efficiently. The Scanning Electron Microscopy (SEM) Technique and the Fourier Transform Infrared Spectroscopy (FTIR) Method confirmed the covalent bonding success and the excellent carrier characteristics. Thus, the immobilization yield reached 73.5% and the optimum temperature was shifted from 40 to 65 °C. The immobilized lipase kept 80% of its total activity after 10 cycles and had 3 and 3.2-fold half-lives at 70, and 80 °C respectively compared to the free enzyme.

New Recombinant Cold-Adapted and Organic Solvent Tolerant Lipase from Psychrophilic Pseudomonas sp. LSK25, Isolated from Signy Island Antarctica

In recent years, studies on psychrophilic lipases have become an emerging area of research in the field of enzymology. The study described here focuses on the cold-adapted organic solvent tolerant lipase strain Pseudomonas sp. LSK25 isolated from Signy Station, South Orkney Islands, maritime Antarctic. Strain LSK25 lipase was successfully cloned, sequenced, and over-expressed in an Escherichia coli system. Sequence analysis revealed that the lipase gene of Pseudomonas sp. LSK25 consists of 1432 bp, lacks an N-terminal signal peptide and encodes a mature protein consisting of 476 amino acids. The recombinant LSK25 lipase was purified by single-step purification using Ni-Sepharose affinity chromatography and had a molecular mass of approximately 65 kDa. The final recovery and purification fold were 44% and 1.3, respectively. The LSK25 lipase was optimally active at 30 °C and at pH 6. Stable lipolytic activity was reported between temperatures of 5–30 °C and at pH 6–8. A significant enhancement of lipolytic activity was observed in the presence of Ca²⁺ ions, the organic lipids of rice bran oil and coconut oil, a synthetic C12 ester and a wide range of water immiscible organic solvents. Overall, lipase strain LSK25 is a potentially desirable candidate for biotechnological application, due to its stability at low temperatures, across a range of pH and in organic solvents.

Purification and characterization of halophilic lipase of Chromohalobacter sp. from ancient salt well

A halophilic lipase (LipS2) was produced by Chromohalobacter canadensis strain which was isolated from ancient salt well of Zigong, China. LipS2 was purified to homogeneity and showed a single band with molecular mass of 58 kDa by SDS-PAGE. LipS2 preferred middle-to-long acyl chain esters with C14 triglycerides as optimum substrate. It was noteworthy that LipS2 displayed efficient hydrolysis activity to some vegetable oils which were composed of polyunsaturated fatty acid. LipS2 showed high activity in range of 2.5-3.5 M NaCl, no activity without salt. Optimum temperature and pH were 55 °C and pH 8.5, respectively. Notably, the thermostability and pH stability of LipS2, varying with salt concentration, reached optimum in the presence of 3.0 M NaCl. LipS2 was stimulated by Ca²⁺ and Mg²⁺ , inhibited by Zn²⁺ , Cu²⁺ , Mn²⁺ , Fe²⁺ , and Hg²⁺ . Moreover, LipS2 displayed significant tolerance to organic solvents including methanol, ethanol, ethyl acetate and acetone, especially, LipS2 activity was enhanced markedly by the hexane and benzene. Non-ionic surfactants increased LipS2 activity, while ionic surfactants decreased activity. This was the first report on halophilic lipase of Chromohalobacter from ancient salt well. The results suggested that LipS2 may have considerable potential for biotechnological applications.

A cold and organic solvent tolerant lipase produced by Antarctic strain Rhodotorula sp. Y-23

Psychrotolerant yeast Rhodotorula sp. Y-23 was isolated from the sediment core sub-samples of Nella Lake, East Antarctica. Isolate was screened for lipase production using plate assay method followed by submerged fermentation. Production optimization revealed the maximum lipase production by using palmolein oil (5% v/v), pH 8.0 and inoculum size of 2.5% v/v at 15 °C. The potential inducers for lipase were 1% w/v of galactose and KNO₃ , and MnCl₂ (0.1% w/v). Final productions with optimized conditions gave 5.47-fold increase in lipase production. Dialyzed product gave a purification fold of 5.63 with specific activity of 26.83 U mg^-1 and 15.67% yields. This lipase was more stable at pH 5.0 and -20 °C whereas more activity was found at pH 8.0 and 35 °C. Stability was more in 50 mM Fe³⁺ , EDTA-Na (20 mM), sodium deoxycholate (20 mM), H₂ O₂ (1% v/v), and almost all organic solvents (50% v/v). Tolerance capacity at wider range of pH and temperature with having lower K_m value i.e., 0.08 mg ml^-1 and higher V_max 385.68 U mg^-1 at 15 °C make the studied lipase useful for industrial applications. Besides this, the lipase was compatible with commercially available detergents, and its addition to them increases lipid degradation performances making it a potential candidate in detergent formulation.

Biotechnological perspectives of microorganisms isolated from the Polar Regions

Polar permanently frozen grounds cover more than 20% of the earth's surface, and about 60% of the Russian territories are permafrost. In the permafrost environments, the combination of low temperature and poor availability of liquid water make these habitats extremely inhospitable for life. To date, both culture-dependent and culture-independent methods have shown that permafrost is a habitat for microorganisms of all three domains: Bacteria, Archaea and Eukarya. An overview of applying psychrophilic and psychrotolerant bacteria and archaea isolated from Arctic and Antarctic permafrost ecosystems in biotechnological processes of wastewater treatment, production of cold-adapted enzymes, etc. is discussed here. The study of existing collections of microorganisms isolated from permanently cold habitats, improved methods of sampling and enrichment will increase the potential biotechnological applications of permafrost bacteria and archaea producing unique biomolecules.

Lipases: An Overview

Lipases are ubiquitous enzymes, widespread in nature. They were first isolated from bacteria in the early nineteenth century, and the associated research continuously increased due to the characteristics of these enzymes. This chapter reviews the main sources, structural properties, and industrial applications of these highly studied enzymes.

The biology and the importance of Photobacterium species

Photobacterium species are Gram-negative coccobacilli which are distributed in marine habitats worldwide. Some species are unique because of their capability to produce luminescence. Taxonomically, about 23 species and 2 subspecies are validated to date. Genomes from a few Photobacterium spp. have been sequenced and studied. They are considered a special group of bacteria because some species are capable of producing essential polyunsaturated fatty acids, antibacterial compounds, lipases, esterases and asparaginases. They are also used as biosensors in food and environmental monitoring and detectors of drown victim, as well as an important symbiont.

Prolonged Production and Aggregation Complexity of Cold-Active Lipase from Pseudomonas proteolytica (GBPI_Hb61) Isolated from Cold Desert Himalaya

Pseudomonas, being the common inhabitant of colder environments, are suitable for the production of cold-active enzymes. In the present study, a newly isolated strain of Pseudomonas from cold desert site in Indian Himalayan Region, was investigated for the production of cold-active lipase. The bacteria were identified as Pseudomonas proteolytica by 16S rDNA sequencing. Lipase production by bacteria was confirmed by qualitative assay using tributyrin and rhodamine-B agar plate method. The bacterium produced maximum lipase at 25 °C followed by production at 15 °C while utilizing olive, corn, as well as soybean oil as substrate in lipase production broth. Enzyme produced by bacteria was partially purified using ammonium sulphate fractionation. GBPI_Hb61 showed aggregation behaviour which was confirmed using several techniques including gel filtration chromatography, dynamic light scattering, and native PAGE. Molecular weight determined by SDS-PAGE followed by in-gel activity suggested two lipases of nearly similar molecular weight of ~50 kDa. The enzyme showed stability in wide range of pH from 5 to 11 and temperature up to 50 °C. The enzyme from GBPI_Hb61 exhibited maximum activity toward p-nitrophenyldecanoate (C10). The stability of enzyme was not affected with methanol while it retained more than 75% activity when incubated with ethanol, acetone, and hexane. The bacterium is likely to be a potential source for production of cold-active lipase with efficient applicability under multiple conditions.

Classification of lipolytic enzymes and their biotechnological applications in the pulping industry

In the pulp and paper industry, during the manufacturing process, the agglomeration of pitch particles (composed of triglycerides, fatty acids, and esters) leads to the formation of black pitch deposits in the pulp and on machinery, which impacts on the process and pulp quality. Traditional methods of pitch prevention and treatment are no longer feasible due to environmental impact and cost. Consequently, there is a need for more efficient and environmentally friendly approaches. The application of lipolytic enzymes, such as lipases and esterases, could be the sustainable solution to this problem. Therefore, an understanding of their structure, mechanism, and sources are essential. In this report, we review the microbial sources for the different groups of lipolytic enzymes, the differences between lipases and esterases, and their potential applications in the pulping industry.

Biodegradation of waste greases and biochemical properties of a novel lipase from Pseudomonas synxantha PS1

A lipase-producing bacterial strain was isolated from oil-well-produced water in Shengli oilfield (Shandong province, China) and was identified as Pseudomonas synxantha by 16S rDNA sequence analysis (named Pseudomonas synxantha PS1). Strain PS1 showed a maximum lipase activity of 10.8 U/mL after culturing for 48 h at 30 °C, with lactose (4 g/L) as carbon source, tryptone (8 g/L) as nitrogen source, olive oil (0.5%, v/v) as inductor, and the initial pH 8.0. Meanwhile, the lipase gene from P. synxantha PS1 was cloned and expressed in Escherichia coli BL21 with the vector pET28a. The novel gene (lipPS1) has an open reading frame of 1425 bp and encodes a 474 aa lipase (LipPS1) sharing the most identity (87%) with the lipase in Pseudomonas fluorescens. LipPS1 preferably acted on substrates with a long chain (C10–C18) of fatty acids. The optimum pH and temperature of the recombinant enzyme were 8.0 and 40 °C, respectively, towards the optimum substrate p-nitrophenyl palmitate. The LipPS1 showed remarkable stability under alkaline conditions and was stable at pH 7.0–10.0 (retaining more than 60% activity). From the organic solvents tests, the lipase was activated by 15% (v/v) methanol (112%), 15% ethanol (127%), and 15% n-butyl alcohol (116%). LipPS1 presented strong biodegradability of waste grease; 93% of waste grease was hydrolyzed into fatty acid after 12 h at 30 °C. This is the first report of the lipase activity and lipase gene obtained from P. synxantha (including wild strain and recombinant strain) and of the recombinant LipPS1 with the detailed enzymatic properties. Also a preliminary study of the biodegradability of waste greases shows the potential value in industry applications.

Characterization of a cold-active esterase from Serratia sp. and improvement of thermostability by directed evolution

BACKGROUND

In recent years, cold-active esterases have received increased attention due to their attractive properties for some industrial applications such as high catalytic activity at low temperatures.

RESULTS

An esterase-encoding gene (estS, 909 bp) from Serratia sp. was identified, cloned and expressed in Escherichia coli DE3 (BL21). The estS encoded a protein (EstS) of 302 amino acids with a predicted molecular weight of 32.5 kDa. It showed the highest activity at 10 °C and pH 8.5. EstS was cold active and retained ~92 % of its original activity at 0 °C. Thermal inactivation analysis showed that the T1/2 value of EstS was 50 min at 50 °C (residual activity 41.23 %) after 1 h incubation. EstS is also quite stable in high salt conditions and displayed better catalytic activity in the presence of 4 M NaCl. To improve the thermo-stability of EstS, variants of estS gene were created by error-prone PCR. A mutant 1-D5 (A43V, R116W, D147N) that showed higher thermo-stability than its wild type predecessor was selected. 1-D5 showed enhanced T1/2 of 70 min at 50 °C and retained 63.29 % of activity after incubation at 50 °C for 60 min, which were about 22 % higher than the wild type (WT). CD spectrum showed that the secondary structure of WT and 1-D5 are more or less similar, but an increase in β-sheets was recorded, which enhanced the thermostability of mutant protein.

CONCLUSION

EstS was a novel cold-active and salt-tolerant esterase and half-life of mutant 1-D5 was enhanced by 1.4 times compared with WT. The features of EstS are interesting and can be exploited for commercial applications. The results have also provided useful information about the structure and function of Est protein.

Expression and characterization of a novel 1,3-regioselective cold-adapted lipase from Rhizomucor endophyticus suitable for biodiesel synthesis

BACKGROUND

The biodiesel production can be carried out by transesterification using either chemical or enzymatic process. The enzymatic transesterification is more promising as it offers an environmental friendly option compared to the chemical process, where the lipases with high catalytic efficiency and good stability play a key role. Hence, it is of great value to identify novel lipases which are suitable for biodiesel production.

RESULTS

A lipase gene (ReLipA) from Rhizomucor endophyticus was cloned and heterologously expressed in Pichia pastoris. ReLipA shared the highest identity of 61 % with the lipases from Rhizopus delemar, Rhizopus oryzae, and Saccharomyces cerevisiae. The recombinant lipase (ReLipA) was secreted as an active protein with the highest activity of 1961 U mL(-1) in a 5-L fermentor by high cell-density fermentation. ReLipA was purified to homogeneity with a recovery yield of 75.7 %. The purified enzyme was most active at pH 6.0 and 40 °C, respectively, and it was stable up to 55 °C. ReLipA displayed 75 % of its maximal activity at 0 °C, indicating that it is a cold-adapted lipase. It exhibited broad substrate specificity toward various p-nitrophenyl esters and triglycerides. ReLipA hydrolyzed triolein to release mainly 1,2-diolein without the formation of 1,3-diolein, suggesting that it is a sn-1,3 regiospecific lipase. Furthermore, ReLipA synthesized different types of oleates by esterification using oleic acid and short chain alcohols (e.g., methanol, ethanol, and butanol) as the substrates with the highest conversion yield of 82.2 %. Therefore, the cold-adapted lipase may be a good biocatalyst in ester synthesis in biodiesel industry.

CONCLUSIONS

A novel cold-adapted lipase was identified and characterized. The high yield and excellent properties may confer the enzyme with great potential for biodiesel production in bioenergy industry. This is the first report on a cold-adapted lipase from Rhizomucor species.

Cold and Hot Extremozymes: Industrial Relevance and Current Trends

The development of enzymes for industrial applications relies heavily on the use of microorganisms. The intrinsic properties of microbial enzymes, e.g., consistency, reproducibility, and high yields along with many others, have pushed their introduction into a wide range of products and industrial processes. Extremophilic microorganisms represent an underutilized and innovative source of novel enzymes. These microorganisms have developed unique mechanisms and molecular means to cope with extreme temperatures, acidic and basic pH, high salinity, high radiation, low water activity, and high metal concentrations among other environmental conditions. Extremophile-derived enzymes, or extremozymes, are able to catalyze chemical reactions under harsh conditions, like those found in industrial processes, which were previously not thought to be conducive for enzymatic activity. Due to their optimal activity and stability under extreme conditions, extremozymes offer new catalytic alternatives for current industrial applications. These extremozymes also represent the cornerstone for the development of environmentally friendly, efficient, and sustainable industrial technologies. Many advances in industrial biocatalysis have been achieved in recent years; however, the potential of biocatalysis through the use of extremozymes is far from being fully realized. In this article, the adaptations and significance of psychrophilic, thermophilic, and hyperthermophilic enzymes, and their applications in selected industrial markets will be reviewed. Also, the current challenges in the development and mass production of extremozymes as well as future prospects and trends for their biotechnological application will be discussed.