Synthesis of surface modified/multi-functional nanoparticles has become a vital research area of material science. In the present work, iron oxide (Fe3O4) nanoparticles prepared by solvo-thermal method were functionalized by polydopamine. The catechol groups of polydopamine at the surface of nanoparticles provided the sites for the attachment of Aspergillus terreus AH-F2 lipase through adsorption, Schiff base and Michael addition mechanisms. The strategy was revealed to be facile and efficacious, as lipase immobilized on magnetic nanoparticles grant the edge of ease in recovery with utilizing external magnet and reusability of lipase. Maximum activity of free lipase was estimated to be 18.32 U/mg/min while activity of Fe3O4-PDA-Lipase was 17.82 U/mg/min (showing 97.27% residual activity). The lipase immobilized on polydopamine coated iron oxide (Fe3O4_PDA_Lipase) revealed better adoptability towards higher levels of temperature/pH comparative to free lipase. The synthesized (Fe3O4_PDA_Lipase) catalyst was employed for the preparation of biodiesel from waste cooking oil by enzymatic transesterification. Five factors response surface methodology was adopted for optimizing reaction conditions. The highest yield of biodiesel (92%) was achieved at 10% Fe3O4_PDA_Lipase percentage concentration, 6:1 CH3OH to oil ratio, 37 °C temperature, 0.6% water content and 30 h of reaction time. The Fe3O4-PDA-Lipase activity was not very affected after first four cycles and retained 25.79% of its initial activity after seven cycles. The nanoparticles were characterized by FTIR (Fourier transfer infrared) Spectroscopy, XRD (X-ray diffraction) and TEM (transmission electron microscopy), grafting of polydopamine on nanoparticles was confirmed by FTIR and formation of biodiesel was evaluated by FTIR and GC-MS (gas chromatography-mass spectrometry) analysis.

Antimicrobials used to treat burn wound infections have become multidrug-resistant, thus delaying wound healing. When combined with silver nanoparticles, antibiotics create a multifaceted antibacterial mechanism of action to which bacteria are incapable of developing resistance. Similarly, the amniotic membrane has been found to lower the bacterial number. The purpose of the current study was to observe the antibacterial activity of combined topical colistin with silver nanoparticles and decellularized human amniotic membrane as a dressing in burn wounds infected with bacteria with the goal of promoting faster healing. Bacteria commonly isolated from burn wounds and the most sensitive topical antibiotic were identified. Colistin, silver nanoparticles and combined colistin with silver nanoparticles were impregnated into decellularized human amniotic membranes. These wound dressings were evaluated in third-degree multidrug-resistant bacterial infected thermal burns induced in rats. Out of a total of 708 pus samples from burn wounds, Pseudomonas aeruginosa was the most prevalent pathogen 308 (43.5%), followed by Klebsiella pneumoniae 300 (42.4%). Topical colistin was 100% sensitive for both bacteria. Overall, maximum wound contraction (p < 0.05), and increased collagen deposition (+++) with no isolation of bacteria from wound swabs were noted on day 21 for the combined colistin with silver nanoparticle-loaded human amniotic membrane dressing group. Our study concluded that the increased antimicrobial activity of the novel combination of colistin and silver nanoparticle-loaded decellularized human amniotic membrane manifested its potential as an effective burn wound dressing.

The analysis of fatty acids methyl esters showed the similar composition of microbial oil as in vegetable oils and high amount of methyl esters were obtained after transesterification. Therefore, potentially oleaginous yeast could be used to generate a large amount of lipids for biodiesel production that will be the better substitute of petroleum-based diesel and will also control the environmental pollution.

This study is the first report about isolation, purification and optimization of lipase from Bacillus glycinifermentans. In this study, Bacillus glycinifermentansMK-840989 was isolated from a local petrol pump. The bacterium showed lipolytic zones of 0.19cm, 0.044cm, and 0.28cm on peptone yeast agar, olive oil hydrolysis agar and chromogenic plate agar, respectively. B. glycinifermentans also produced an extracellular lipase (55.1µmol/ml). This bacterium preferred acidic environment (pH 5) for growing optimally at 80˚C when the medium was supplemented with 1% olive oil. The olive oil induced its growth up to 9h. The protein content of the purified lipase was estimated about 75mg/ml as compared to its crude form, i.e. 350mg/ml. The purified lipase was found to be thermostable acidic in nature as its optimum activity was observed at 90˚C (0.08U/ml) and pH 5 (0.02U/ml). Other optimization factors included 1% olive oil (0.065U/ml), 0.1mM maltose (0.023U/ml), 0.1mM Ca (0.025U/ml), 1% yeast extract (16.8U/ml), 1% wheat waste (0.019U/ml), 1% commercial detergent (0.016U/ml) and 1% tween-20 (0.015 U/ml). The purified lipase showed a polypeptide of 26.7kDa on SDS-PAGE. These features such as thermostability, acidic nature, ability to show activity in wheat waste and tolerance to detergents render the lipase of B.glycinifermentans MK-840989 as an attractive choice for biotechnologists to employ it at industrial level. The purified lipase of B.glycinifermentans MK-840989 can be a potential candidate for detergent and oil-remediation industry. It can help to replace conventional synthetic detergent as it is cost-effective and eco-friendly.

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