Enhanced lipase production from organic solvent tolerant Pseudomonas aeruginosa UKHL1 and its application in oily waste-water treatment

Cold-active lipase from Psychrobacter alimentarius ILMKVIT and its application in selective enrichment of ω-3 polyunsaturated fatty acids in flax seed oil

Lipases are one of the ubiquitous enzymes that belong to the hydrolases family and have a wide variety of applications. Cold-active lipases are of major attraction as they can act in lower temperatures and low water conditions because of their inherent greater flexibility. One of the novel applications of lipase is the enrichment of ω-3 polyunsaturated fatty acids (PUFA) in plant and fish oils. This study is aimed at the isolation and identification of cold-active lipase producing bacterium from marine sources, preliminary optimization of medium constituents and conditions, purification of lipase using chromatographic techniques, biochemical characterization, and ultimately the exploration of its application in the enrichment of ω-3 PUFA in flax seed oil. Psychrobacter alimentarius ILMKVIT was identified as the potential cold-active lipase producing bacterium based on its lipolytic activity in rhodamine B agar, titrimetric, and p-nitrophenyl palmitate (p-NPP) assays. One factor at a time (OFAT) analysis, revealed, an incubation time of 4.5 days, alkaline pH of 9, the temperature of 25 °C, peptone, and yeast extract as nitrogen sources, olive oil as inducer sources, 1% inoculum size, and NaCl as mineral sources as optimum production medium constituents and conditions for lipase production. Lipase purification was achieved by ion exchange and gel-filtration chromatography with a 9.27% yield and 37.51-fold purification. Biochemical characterization reported that the lipase is cold-active, alkaline, enhanced by Fe3+ metal ions, and tolerant to organic solvents, detergents, and inhibitors. P. alimentarius ILMKVIT lipase-hydrolysis followed by urea complexation of flax seed oil resulted in the enrichment of ω-3 PUFA, especially α-linolenic acid (ALA). Hence, the novel cold-active lipase from P. alimentarius ILMKVIT could be used to enrich ω-3 PUFA in flax seed oil and developed further as a prominent nutrient supplement for health benefits.

Evaluation of wool protein hydrolysate as peptone for production of microbial enzymes

Peptones are one of the most expensive components of microbial culture media. The present study was conducted to test the usability of low-cost sheep wool peptone (SWP) as an organic nitrogen source in the production of six industrially important enzymes (lipase, amylase, tannase, pectinase, cellulase and invertase). SWP was prepared by alkaline hydrolysis and acid neutralization. Bacillus licheniformis and Aspergillus niger were selected as test microorganisms for enzyme production. To evaluate the efficacy of SWP in enzyme production, it was compared with commercial tryptone peptone (TP) in the shaking flask cultures of the test microorganisms. The optimum concentration of both SWP and TP was determined to be 8 g/L for the production of B. licheniformis-derived enzymes, but 6 g/L for the production of A. niger-derived enzymes. It was determined that SWP was superior to TP in the production of four enzymes (lipase, amylase, tannase and pectinase) of both B. licheniformis and A. niger. This is the first study about the usage of sheep wool protein hydrolysate (SWP) as an organic nitrogen source or a peptone in fermentative production of microbial enzymes.

Listeria monocytogenes is a solvent tolerant organism secreting a solvent stable lipase: potential biotechnological applications

Purpose

The emerging biobased economy will require robust, adaptable, organisms for the production and processing of biomaterials as well as for bioremediation. Recently, the search for solvent tolerant organisms and solvent tolerant enzymes has intensified. Resilient organisms secreting solvent stable lipases are of particular interest for biotechnological applications.

Methods

Screening of soil samples for lipase-producing organisms was carried out on Rhodamine B plates. The most productive lipase-producing organisms were further screened for their resistance to solvents commonly used in biotechnological applications.

Results

In the course of screening, one of the isolated organisms that exhibited extracellular lipase activity, was identified as the human pathogen Listeria monocytogenes through 16S rRNA sequencing. Further exploration revealed that this organism was resistant to solvents ranging from log P − 0.81 to 4.0. Moreover, in the presence of these solvents, L. monocytogenes secreted an extracellular, solvent tolerant, lipase activity. This lipase retained approximately 80% activity when incubated in 30% (v/v) methanol for 24 h.

Conclusion

These findings identify L. monocytogenes as a potentially useful organism for biotechnological applications. However, the fact that Listeria is a pathogen is problematic and it will require the use of non-pathogenic or attenuated Listeria strains for practical applications. Nonetheless, the ability to adapt to rapidly changing environmental conditions, to grow at low temperatures, to resist solvents and to secrete an extracellular solvent tolerant lipase are unique and highly useful characteristics. The potential application of L. monocytogenes in wastewater bioremediation and plastics degradation is discussed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10529-022-03284-5.

Draft Genome Analysis of Acinetobacter indicus Strain UBT1, an Efficient Lipase and Biosurfactant Producer

Acinetobacter indicus strain UBT1 has shown efficient lipase (243 U ml^-1) and biosurfactant (61.1% E24% emulsification and surface tension reduction to 37.7 mN m^-1) production capabilities using agro-industrial waste as sole carbon source. We report here the draft genome sequence of A. indicus strain UBT1 having genome size of 2.97 Mb with 45.90% GC content. Total 2721 coding genes were predicted using National Center for Biotechnology Information-Prokaryotic Genome Annotation Pipeline (NCBI-PGAP). The whole genome shotgun project sequence data are accessible through NCBI Gene Bank under accession no. JABFOI000000000. PGAP annotation revealed the presence of the triacylglycerol lipase, phospholipase etc., that circuitously confers the oil consumption competency to the strain UBT1. Rapid Annotation using the Subsystem Technology (RAST) server used for mapping the genes to the subsystem resulted in 278 subsystem with 30% subsystem coverage. The draft genome data can be used to exploit the A. indicus strain UBT1 for its advance biotechnological application and also for further comparative genomic studies.