Production and properties of an alkaline, thermophilic lipase from Pseudomonas fluorescens NS2W

Marine Bacterial Esterases: Emerging Biocatalysts for Industrial Applications

The marine ecosystem has been known to be a significant source of novel enzymes. Esterase enzymes (EC 3.1.1.1) represent a diverse group of hydrolases that catalyze the cleavage and formation of ester bonds. Although esterases are widely distributed among marine organisms, only microbial esterases are of paramount industrial importance. This article discusses the importance of marine microbial esterases, their biochemical and kinetic properties, and their stability under extreme conditions. Since culture-dependent techniques provide limited insights into microbial diversity of the marine ecosystem, therefore, genomics and metagenomics approaches have widely been adopted in search of novel esterases. Additionally, the article also explains industrial applications of marine bacterial esterases particularly for the synthesis of optically pure substances, the preparation of enantiomerically pure drugs, the degradation of human-made plastics and organophosphorus compounds, degradation of the lipophilic components of the ink, and production of short-chain flavor esters.

Hydrocarbon-associated substrates reveal promising fungi for poly (ethylene terephthalate) (PET) depolymerization

Recalcitrant characteristics and insolubility in water make the disposal of synthetic polymers a great environmental problem to be faced by modern society. Strategies towards the recycling of post-consumer polymers, like poly (ethylene terephthalate, PET) degradation/depolymerization have been studied but still need improvement. To contribute with this purpose, 100 fungal strains from hydrocarbon-associated environments were screened for lipase and esterase activities by plate assays and high-throughput screening (HTS), using short- and long-chain fluorogenic probes. Nine isolates were selected for their outstanding hydrolytic activity, comprising the genera Microsphaeropsis, Mucor, Trichoderma, Westerdykella, and Pycnidiophora. Two strains of Microsphaeropsis arundinis were able to convert 2-3% of PET nanoparticle into terephthalic acid, and when cultured with two kinds of commercial PET bottle fragments, they also promoted weight loss, surface and chemical changes, increased lipase and esterase activities, and led to PET depolymerization with release of terephthalic acid at concentrations above 20.0 ppm and other oligomers over 0.6 ppm. The results corroborate that hydrocarbon-associated areas are important source of microorganisms for application in environmental technologies, and the sources investigated revealed important strains with potential for PET depolymerization.

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.

Production and Characterization of Lipases by Two New Isolates of Aspergillus through Solid-State and Submerged Fermentation

Due to the numerous applications of lipases in industry, there is a need to study their characteristics, because lipases obtained from different sources may present different properties. The aim of this work was to accomplish the partial characterization of lipases obtained through submerged fermentation and solid-state fermentation by two species of Aspergillus. Fungal strains were isolated from a diesel-contaminated soil and selected as good lipases producers. Lipases obtained through submerged fermentation presented optimal activities at 37°C and pH 7.2 and those obtained through solid-state fermentation at 35°C and pH 6.0. The enzymes produced by submerged fermentation were more temperature-stable than those obtained by solid-state fermentation, presenting 72% of residual activity after one hour of exposition at 90°C. Lipases obtained through submerged fermentation had 80% of stability in acidic pH and those obtained through solid-state fermentation had stability greater than 60% in alkaline pH.

Clavulanic acid production by the MMS 150 mutant obtained from wild type Streptomyces clavuligerus ATCC 27064

Clavulanic acid (CA) is a powerful inhibitor of the beta-lactamases, enzymes produced by bacteria resistants to penicillin and cefalosporin. This molecule is produced industrially by strains of Streptomyces clavuligerus in complex media which carbon and nitrogen resources are supplied by inexpensive compounds still providing high productivity. The genetic production improvement using physical and chemical mutagenic agents is an important strategy in programs of industrial production development of bioactive metabolites. However, parental strains are susceptible to loss of their original productivity due genetic instability phenomenona. In this work, some S. clavuligerus mutant strains obtained by treatment with UV light and with MMS are compared with the wild type (Streptomyces clavuligerus ATCC 27064). The results indicated that the random mutations originated some strains with different phenotypes, most divergent demonstrated by the mutants strains named AC116, MMS 150 and MMS 54, that exhibited lack of pigmentation in their mature spores. Also, the strain MMS 150 presented a larger production of CA when cultivated in semi-synthetics media. Using other media, the wild type strain obtained a larger CA production. Besides, using the modifed complex media the MMS 150 strain showed changes in its lipolitic activity and a larger production of CA. The studies also allowed finding the best conditions for a lipase activity exhibited by wild type S. clavuligerus and the MMS150 mutant.

Optimization of extracellular thermophilic highly alkaline lipase from thermophilic bacillus sp isolated from hotspring of Arunachal Pradesh, India

Studies on lipase production were carried out with a bacterial strain (Bacillus sp LBN 2) isolated from soil sample of hotspring of Arunachal Pradesh, India. The cells were cultivated in a mineral medium with maximum production at 1% groundnut oil. The optimum temperature and initial medium pH for lipase production by the organism were 50⁰C and 9.0 respectively. The molecular mass was found to be 33KDa by SDS PAGE. The optimal pH and temperature for activity were 10 and 60⁰C respectively. The enzyme was found to be stable in the pH range of 8–11 with 90% retention of activity at pH 11. The enzyme retained 90% activity at 60⁰C and 70% of activity at 70⁰C for 1h. The lipase was found to be stable in acetone followed by ethanol. The present findings suggested the enzyme to be thermophilic alkaline lipase.

A thermostable lipase produced by a newly isolated Geotrichum-like strain, R59

Growth and production of lipase by a new Geotrichum-like strain, R59, were studied. Production of extracellular lipase was substantially enhanced when the initial pH of the culture medium, types of carbon and nitrogen sources, substances probably stimulating the lipase biosynthesis, the temperature, and time of growth were optimized. Sucrose and triolein were the most effective carbon sources for lipase production. Maximum lipase activity (146 U/ml(-1)) was obtained with urea as the nitrogen source. Growth at 30 degrees C, an initial pH of 6.0 and incubation time of 48 h were found as optimum conditions for cell growth and production of lipase by Geotrichum-like strain R59. The enzyme was thermostable and exhibited very high activity after 1 h incubation at 60 degrees C.