Cancer is one of the major deadly diseases globally. The alarming rise in the mortality rate due to this disease attracks attention towards discovering potent anticancer agents to overcome its mortality rate. The discovery of novel and effective anticancer agents from natural sources has been the main point of interest in pharmaceutical research because of attractive natural therapeutic agents with an immense chemical diversity in species of animals, plants, and microorganisms. More than 60% of contemporary anticancer drugs, in one form or another, have originated from natural sources. Plants and microbial species are chosen based on their composition, ecology, phytochemical, and ethnopharmacological properties. Plants and their derivatives have played a significant role in producing effective anticancer agents. Some plant derivatives include vincristine, vinblastine, irinotecan, topotecan, etoposide, podophyllotoxin, and paclitaxel. Based on their particular activity, a number of other plant-derived bioactive compounds are in the clinical development phase against cancer, such as gimatecan, elomotecan, etc. Additionally, the conjugation of natural compounds with anti-cancerous drugs, or some polymeric carriers particularly targeted to epitopes on the site of interest to tumors, can generate effective targeted treatment therapies. Cognizance from such pharmaceutical research studies would yield alternative drug development strategies through natural sources which could be economical, more reliable, and safe to use.

The biogenesis of silver nanoparticles by fungi is an ecologically clean and nontoxic method compared to other physical and chemical methods. Thus, we aimed to discuss the mycosynthesis of extracellular size-controlled AgNPs. After comprehensive screening, Aspergillus fumigatus BTCB10 (KY486782) was selected for the synthesis of AgNPs of controlled size. Characterization was performed by UV-Vis spectrophotometer, Zetasizer, X-Ray Diffraction (XRD), FTIR (Fourier-transform infrared), Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) along with functional assays—antibacterial and MTT assays. Data suggested that under optimized conditions, i.e., temperature 25°C, AgNO₃ concentration 1 mM, biomass 7 g, fungal culture age 7 days, pH 6, ratio of cell-free filtrate (CFF)/silver nitrate (3 : 2), NaCl 20%, and under dark light, the smallest size AgNPs of 0.681 nm with 100% monodispersity was obtained as evident by a zeta potential of -23.4 mV, UV-Vis band at 400 nm, and the presence of O-H and C=O groups confirmed by ATR-FTIR; XRD revealed the crystalline nature of AgNPs; additionally, cube-shaped AgNPs were revealed by Scanning Electron Microscopy (SEM). Moreover, synthesized AgNPs exhibited antibacterial activity against multidrug-resistant bacterial strains, notably, Klebsiella pneumoniae BTCB04, Acinetobacter BTCB05, Pseudomonas aeruginosa BTCB01, and Escherichia coli BTCB03, while maximum 7-fold was observed with Acinetobacter BTCB05. AgNPs demonstrated no cytotoxic activity against HepG2 cells; however, in combination with cisplatin, antiproliferative and cytotoxic effects became more evident and significant in comparison to control and as single agent. Taken together, the data suggested that economical and smallest size AgNPs can be biosynthesized from Aspergillus fumigatus BTCB10 and be used as antibacterial and antiproliferative agents in combination with current drugs against clinically relevant multiple drug-resistant bacterial and tumoral cells. Further studies are required to confirm their effects employing in vivo disease models.

In the present study, Alcaligenes aquatilis was found to decolorize 82% Synazol red 6HBN after incubation of 4 days at 37 °C and pH 7. Maximum decolorization was found under static conditions by using saw dust and yeast extract as carbon and nitrogen source. It also showed promising potential to decolorize mixture of multiple dyes at a rate of more than 86% in 5 days. Decolorization of dye had positive influence on the growth of bacterium as growth rate was increased along with decolorization. The cleavage of azo bond was confirmed through TLC, HPLC and GC–MS analysis. The dye metabolites produced during bacterial treatment are linked to various pathways including ATP synthesis process. The absence of peaks of wavelength 1612/cm and 1532/cm in bacterially treated FTIR sample demonstrated the cleavage of azo bond. Microbial growth in decolorized dye wastewater shows that bacterially decolorized wastewater is unharmful for the growth of micro-flora. The high decolorization ability of A. aquatilis 3c to convert toxic azo dyes into useful end products may find potential applications in the environmental biotechnology.

Cadmium resistant bacterium, isolated from industrial wastewater, was characterized as Salmonella enterica 43C on the basis of biochemical and 16S rRNA ribotyping. It is first ever reported S. enterica 43C bared extreme resistance against heavy metal consortia in order of Pb2+>Cd2+>As3+>Zn2+>Cr6+>Cu2+>Hg2+. Cd2+ stress altered growth pattern of the bacterium in time dependent manner. It could remove nearly 57 % Cd2+ from the medium over a period of 8 days. Kinetic and thermodynamic studies based on various adsorption isotherm models (Langmuir and Freundlich) depicted the Cd2+ biosorption as spontaneous, feasible and endothermic in nature. Interestingly, the bacterium followed pseudo first order kinetics, making it a good biosorbent for heavy metal ions. The S. enterica 43C Cd2+ processivity was significantly influenced by temperature, pH, initial Cd2+ concentration, biomass dosage and co-metal ions. FTIR analysis of the bacterium revealed the active participation of amide and carbonyl moieties in Cd2+ adsorption confirmed by EDX analysis. Electron micrographs beckoned further surface adsorption and increased bacterial size due to intracellular Cd2+ accumulation. An overwhelming increase in glutathione and other non-protein thiols levels played a significant role in thriving oxidative stress generated by metal cations. Presence of metallothionein clearly depicted the role of such proteins in bacterial metal resistance mechanism. The present study results clearly declare S. enterica 43C a suitable candidate for green chemistry to bioremediate environmental Cd2+.