Potential of Antarctic lipase from Acinetobacter johnsonii Ant12 for treatment of lipid-rich wastewater: screening, production, properties and applications.

The present study aimed to screen and optimize lipase production by the Antarctic strain Acinetobacter johnsonii Ant12 for lipid-rich wastewater treatment. Lipase production was successfully enhanced threefold through optimization of culture conditions. The optimum crude lipase activity was observed at 50 °C with high stability in a wide temperature range. The lipase also exhibited high activity and stability in the presence of solvents, metal ions, and surfactants. The crude lipase was used for the treatment of lipid-rich wastewater, which poses a significant challenge, as traditional removal methods are often inefficient or non-eco-friendly. In this study, bioaugmentation with Ant12 resulted in substantial lipid reduction in synthetic as well as real-world wastewater. Multiple linear regression analysis showed that lipid concentration and time were the most significant factors influencing lipid degradation. Bioaugmentation of real-world wastewater with Ant12 cells resulted in 84% removal of lipids in 72 h, while its crude lipase degraded 73.7% of lipids after 24 h. Thus, the specific rate of lipid degradation was higher for crude lipase (0.095/h) than the whole cell treatment (0.031/h). Economic analysis revealed that crude lipase production was much cheaper, faster and more eco-friendly than purified or partially purified lipase production, which justifies its use in wastewater treatment. The high activity of enzyme also implicates its application as a detergent additive. In our knowledge, it is the first study to establish A. johnsonii isolate from Antarctica for lipid-rich wastewater treatment.

Screening, identification, and characterization of lipase-producing halotolerant Bacillus altitudinis Ant19 from Antarctic soil.

Potent lipase-producing and halotolerant Bacillus altitudinis Ant19 strain was screened and isolated from Antarctic soil. The isolate showed broad-range lipase activity against different lipid substrates. Presence of lipase activity was confirmed by PCR amplification and sequencing of the lipase gene from Ant19. The study attempted to establish the use of crude extracellular lipase extract as cheap alternative to purified enzyme by characterizing the crude lipase activity and testing it in certain practical applications. Crude lipase extract from Ant19 showed high stability at 5-28 â„ƒ (> 97%), while lipase activity was noted in a wide temperature range of 20-60 â„ƒ (> 69%), with optimum activity at 40 â„ƒ (117.6%). The optimum lipolytic activity was noted at pH 8 with good activity and stability in alkaline conditions (pH 7-10). Moreover, the lipase activity was substantially stable in various solvents, commercial detergents, and surfactants. It retained 97.4% activity in 1% solution of commercial Nirma detergent. Besides, it was non-regiospecific, and active against substrates having different fatty acid chain lengths with preference for shorter chain length. Further, the crude lipase enhanced the oil stain removal efficiency of commercial detergent from 52 to 77.9%, while 66% oil stain was removed using crude lipase alone. Immobilization process improved the storage stability of crude lipase for 90 days. In our knowledge, it is the first study on characterization of lipase activity from B. altitudinis, which has promising applications in various fields.

Isolation and Enrichment of Bacteriophages by Membrane Filtration Immobilization Technique.

The method described here enables rapid bacteriophage isolation and enrichment of host-specific bacteriophages from an environmental sample. This is achieved by using a simple 0.45-µm Millipore membrane where a specific host is immobilized on the membrane and a sample suspected of containing bacteriophages is exposed to the immobilized cells with the help of a membrane filtration unit. This filtration step facilitates host-specific interaction of bacteriophages with the host and maximization of this interaction using a classic membrane filtration method. Under the effect of vacuum from a vacuum pump, a filter assembly provides a chance for every bacteriophage in the sample to interact with the specific host on the membrane filter. Our technique allows retaining specific bacteriophages on the membrane along with its host cells via adsorption; these adsorbed bacteriophages (along with their hosts) on a filter disc are then enriched in regular nutritive broth, tryptone soya broth (TSB), by incubation. With help of a plaque assay method, host-specific phages of various bacterial species can be isolated, segregated, and enriched. © 2018 by John Wiley & Sons, Inc.