Influence of culture conditions on lipase production byBacillus sp. FH5

Production strategies and biotechnological relevance of microbial lipases: a review

Lipases are enzymes that catalyze the breakdown of lipids into long-chain fatty acids and glycerol in oil-water interface. In addition, they catalyze broad spectrum of bioconversion reactions including esterification, inter-esterification, among others in non-aqueous and micro-aqueous milieu. Lipases are universally produced from plants, animals, and microorganisms. However, lipases from microbial origin are mostly preferred owing to their lower production costs, ease of genetic manipulation etc. The secretion of these biocatalysts by microorganisms is influenced by nutritional and physicochemical parameters. Optimization of the bioprocess parameters enhanced lipase production. In addition, microbial lipases have gained intensified attention for a wide range of applications in food, detergent, and cosmetics industries as well as in environmental bioremediation. This review provides insights into strategies for production of microbial lipases for potential biotechnological applications.

Waste frying oil hydrolysis and lipase production by cold-adapted Pseudomonas yamanorum LP2 under non-sterile culture conditions

Non-sterile culture technique is currently used in some microbial processes. However, there is no study on the use of this technique in the production of microbial lipases and hydrolysis of waste frying oils. This study was conducted to hydrolyse waste frying oils and produce lipase under non-sterile culture conditions using locally isolated cold-adapted bacteria. Of 75 bacterial isolates, the psychrotolerant Pseudomonas yamanorum LP2 (Genbank number: KU711080) was determined to have the highest lipase activity. It was found that a combination of restricted nutrient availability, low temperature and high inoculum volume prevented microbial contaminants under non-sterile conditions. The most favourable parameters for lipase production under both sterile and non-sterile conditions were 15°C temperature, pH 8, 30 mL/L inoculum volume, 40 mL/L waste frying oil concentration, 10 mL/L Tween-80 and 72 h incubation time. The maximum lipase activities in sterile and non-sterile media were determined as 93.3 and 96.8 U/L, respectively. The present process designed for enzyme production and waste oil hydrolysis can reduce the cost of cultivation medium as well as energy consumption and workload. The potential of cold-adapted bacteria to produce lipase and hydrolyse waste oils under non-sterile culture conditions was first tested in the current study.

Understanding why fat, oil and grease (FOG) bioremediation can be unsuccessful

Commercial kitchen wastewaters are typically strong organic and fat-rich effluents, often identified as major contributors to fatberg formation and associated blockages in sewers. Experimental trials were done using synthetic kitchen wastewater to understand the complex reactions involved in microbial remediation in grease traps/separators prior discharge in sewers. The principle organic components (FOG, carbohydrate and protein nitrogen), were varied using ranges observed in a previous study on real kitchen wastewater characterisation. A model bacterium, Bacillus licheniformis NCIMB 9375, was used to evaluate microbial utilisation of the different organic fractions in relation to fat, oil and grease (FOG) degradation. Novel results in the treatment of these effluents showed that, the presence and concentration of alternative carbon sources and the ratio of carbon to nitrogen (COD:N) had great influence on FOG-degradation response. For example, FOG removal decreased from 24 to 10 mg/l/h when glucose was substitute for starch at equivalent concentrations (500 mg/l); and from 26 to 5 mg/l/h when initial COD:N increased from 45:1 to 147:1. The dominant influence of COD:N was validated using a commercial bioadditive and real kitchen wastewater adjusted to different COD:N ratios, confirming the strong influence of kitchen wastewater composition on bioremediation outcomes. These results can therefore have major implications for biological management of FOG in kitchens and sewers as they provide a scientific explanation for bioremediation success or failure.

Noncovalent Immobilization of Yarrowia lipolytica Lipase on Dendritic-Like Amino Acid-Functionalized Silica Nanoparticles

Immobilization of enzymes is a promising approach for the cost-effective application of enzymes. Among others, noncovalent but unleachable approaches for immobilization are one of the most favorable and crucial approaches. Herein, silica nanoparticles are modified by (3-aminopropyl)triethoxysilane (APTES) to generate amino-functionalized silica nanoparticles. Then, the amine functionalities are converted to bifunctional amino acid via post-modification that has zwitterionic properties. This nanostructure with the new functional theme is employed to immobilize Yarrowia lipolytica lipase at room temperature with no further post-modification or cross-linking. This immobilization method is further compared with the metal chelate-based immobilization approach on the same support. The biocatalytic activity of the immobilized lipase is examined under various conditions. The encapsulation of lipase through amino acid-functionalized silica nanoparticles exhibited enhanced stability for the immobilized lipase at higher temperatures and unneutral pHs.

Methods for detection and characterization of lipases: A comprehensive review

Microbial lipases are very prominent biocatalysts because of their ability to catalyze a wide variety of reactions in aqueous and non-aqueous media. The chemo-, regio- and enantio-specific behaviour of these enzymes has caused tremendous interest among scientists and industrialists. Lipases from a large number of bacterial, fungal and a few plant and animal sources have been purified to homogeneity. This article presents a critical review of different strategies which have been employed for the detection, purification and characterization of microbial lipases.