Bioprospecting of aqueous phase from pyrolysis of plant waste residues to disrupt MRSA biofilms.

Methicillin resistant Staphylococcus aureus (MRSA) infections have increased at an alarming rate, recently. In India, stubble burning and air pollution due to the burning of agricultural and forest residues have also increased over the past decade causing environmental and health hazards. This work evaluates the anti-biofilm property of the aqueous phase obtained from pyrolysis of wheat straw (WS AQ) and pine cone (PC AQ) against an MRSA isolate. The WS AQ and PC AQ compositions were determined by GC-MS analysis. The minimum inhibitory concentration was found to be 8% (v v-1) and 5% (v v-1) for WS AQ and PC AQ, respectively. The eradication of biofilms was performed on hospital contact surfaces namely, stainless steel and polypropylene and found to be 51% and 52% for WS AQ and PC AQ, respectively. Compounds identified from the aqueous phase of WS and PC docked against AgrA protein showed good binding scores.

Waste to drugs: identification of pyrolysis by-products as antifungal agents against Cryptococcus neoformans.

The fungi, Cryptococcus neoformans cause major infections such as cryptococcal meningitis and cryptococcosis. Therefore, we explored the use of Thioredoxin reductase (Trr1) from C. neoformans as a gene target for the development of novel antifungal agents. Trr1 plays an essential role in the survival in the oxidative environment of macrophages and is important for the virulence of C. neoformans. During the thermochemical conversion (pyrolysis) of lignocellulosic biomass (LCB), a cocktail of compounds is produced by the decomposition and degradation. In general, LCB-derived cocktail of compounds is a rich source of aromatic compounds that have been shown to be antifungal in nature. Usually, the aqueous phase produced during biomass pyrolysis is generally regarded as waste. Here, we used Parthenium hysterophorus biomass as the antifungal source and obtained the aqueous phase after pyrolysis. Using GC-MS analysis of the aqueous phase collected from P. hysterophorus biomass revealed the presence of a large number of aromatic and organic compounds. Using virtual screening, the compounds present in the aqueous phase were docked against Trr1 using GLIDE. Two promising candidates were analyzed further by performing molecular dynamics simulation using GROMACS, to establish stable interactions. We validated the computational results with clustering analysis. We report that 2,4-Di-tertbutyl phenol and 1H-Pyrazole, 4-ethyl-3,5-dimethyl have a potent antifungal property and we postulate that they could be a potent antifungal agent against Trr1 of C. neoformans.

Production and characterization of microbial levan using sugarcane (Saccharum spp.) juice and chicken feather peptone as a low-cost alternate medium.

An alternate medium consisting of sugarcane juice (SJ) (Saccharum spp.) and chicken feather peptone (CFP) was employed for microbial synthesis of levan. SJ has considerable amounts of vital minerals, vitamins, and amino acids in addition to its major constituent, sucrose. Meanwhile, CFP is also a rich source of essential nutrients such as amino acids, micro and macro elements. Amino acids present in SJ and CFP, such as glutamic acid, arginine, aspartic acid, asparagine and elements such as Ca, Mg favoured the cell growth and levan production. In this present work, levan was produced using Bacillus subtilis MTCC 441 in five different media, namely, sucrose along with defined nutrients (M1), Sugarcane Juice without nutrients (M2), SJ with defined nutrients (M3), SJ along with chicken feather peptone (M4) and sucrose without nutrient (M5). Alternative nutrient medium using SJ and CFP (M4) showed a promising levan yield of 0.32 ± 0.01 g of levan/g of sucrose consumed, which is 64% of the theoretical levan yield possible. Levan produced was characterized using Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography (GPC). There is a change in low molecular weight fractions of levan obtained from SJ and CFP medium compared to the defined medium. Produced levan from the composite medium exhibited strong antioxidant activity and was biocompatible when tested against endothelial cells. The substrate cost was 20% lower than the cost of defined medium. Thus, a composite medium made of SJ and CFP can serve as an alternate low-cost medium for microbial fermentation.

Waste tire particles as efficient materials towards hexavalent chromium removal: Characterisation, adsorption behaviour, equilibrium, and kinetic modelling.

The growing demand for vehicles is increasing every year, and this paves the way for the environmental problem for the generation of the waste tire (WT) and associated disposal after their end life. On the other direction, effluent from tannery and electroplating industries contented with a higher concentration of chromium, which is a toxic pollutant, induces mutation effects. In this work, the approach of reutilization of waste tires as adsorbent is reported towards the sequestrations of hexavalent chromium (Cr(VI)) from the simulated system. The waste tire sample is activated using orthophosphoric acid (H3PO4) and utilized for adsorption studies. Adsorption studies are performed with native tire sample (NTP) and activated tire sample (ATP). About 96.5% of Cr(VI) adsorption efficiency was attained using ATP and at the optimal adsorption solution pH 2.0. The adsorbent performed relatively well in wide a range of initial solution pH tested in the present research. The experimental data analysis of Cr(VI) adsorption onto NTP and ATP revealed the best fit with the kinetic model of pseudo-second-order. Further, the equilibrium data were analysed using two-parameter isotherms, relatively the Langmuir isotherm best represented in both NTP and ATP. ATP demonstrated with higher Cr(VI) removal performance with an adsorption capacity of 102.90 mg/g, according to the Langmuir model. The proposed idea of utilizing waste tire particles as adsorbents in the treatment of Cr(VI) contaminated water offers valuable guidance towards further investigations in the directions of dynamic adsorption and effluent treatment.