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Interest in employing metal oxide nanoparticles as antimicrobial agents is growing. Among various nanoparticles, CuO nanoparticles (NP) has gained vast attention among researchers due to their unusual properties. Various studies has been reported on the antimicrobial activity of CuO NP on microbes. But, no studies can be found on designing suitable reactor for this system. In this study, conventional batch, continuous tubular reactor (CTR), and advanced microfluidic (MF) reactor systems were employed to carry out antimicrobial activity of CuO NP on E Coli..From the experimental results, we observe that minimum cell viability obtained in the batch reactor was about 48.6 %. CTR provided better contact between CuO NPs and E-Coli cells, hence cell viability of 45.3 % was obtained which is lesser than that of batch system. While, in the microfluidic system, when the contact between CuO NPs and E-Coli cells were increased by scaling down the diameter of the channels from 1,200 μm to 600 μm the efficiency of the cell lysis by CuO NP increased from 68.77 % to 95 %. This drastic improvement in cell lysis rates from batch to microchannel is attributed to high surface area to volume ratio and active internal circulation in microfluidic flows. Hence, microfluidic system, which operates at negligible gravity was found to be more efficient in carrying out microbial cell lysis using CuO NP nanoparticles. [ABSTRACT FROM AUTHOR]

In this study, batch removal of hexavalent chromium from aqueous solutions by powdered Colocasia esculenta leaves was investigated. Batch experiments were conducted to study the effects of adsorption of Cr(VI) at different pH values, initial concentrations, agitation speeds, temperatures, and contact times. The biosorbent was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectrometer analysis. The biosorptive capacity of the adsorbent was dependent on the pH of the chromium solution in which maximum removal was observed at pH 2. The adsorption equilibrium data were evaluated for various adsorption isotherm models, kinetic models, and thermodynamics. The equilibrium data fitted well with Freundlich and Halsey models. The adsorption capacity calculated was 47.62 mg/g at pH 2. The adsorption kinetic data were best described by pseudosecond- order kinetic model. Thus, Colocasia esculenta leaves can be considered as one of the efficient and cheap biosorbents for hexavalent chromium removal from aqueous solutions. [ABSTRACT FROM AUTHOR]

The idea of eliminating noxious metal ions from electronic waste contaminated water has led to the use of the metal adsorbing ability of biological matter. The principle of an ion exchanger of biological origin is the key in exhibiting this metal binding feature of microbial biomass. In this study, dead biomass of Aspergillus carbonarius was immobilized using sodium alginate and tested as a biosorbent for hexavalent chromium elimination from effluent. Size and functional groups were characterized for the immobilized bead containing biomass. Optimization of boundary variables like bead size, biosorbent dosage, contact time, pH, and temperature were performed. Maximum elimination of 92.43% hexavalent chromium was achieved at pH 2.0 for 12 h at 37°C, with 20 g/25 mL adsorbent dosage. On application of adsorption isotherms, the data were found to fit Freundlich isotherm and exhibited a high value of correlation coefficient proving the ability of A. carbonarius biomass to act as an effective quencher of hexavalent chromium from electronic waste contaminated water.

Rapid urbanization and industrialization of anthropogenic activities have exerted immense pressure on the environment. Polyhalogenated organic compounds, especially dioxins and furans are regarded as ubiquitously persistent environmental pollutants in the ecosystem. The recalcitrant nature of dioxins and furans induce toxicity in both humans and wildlife. Dioxins and furans are generated by defective technological chemical processes that occur during the manufacture of herbicides and pesticides, use of fertilizers, bleaching of paper and wood pulp and incomplete combustion process. However, incineration and incomplete combustion of solid waste are the main cause for the discharge of dioxins and furans to the environment. During incineration and incomplete combustion, noxious flue gas and ashes are released into the atmosphere and contaminate the soil and water systems; thereby affecting the ecology. According to World Health Organization fact sheet 2016, more than 90% of human exposure to dioxins is through the food chain, especially from dairy products, seafood and meat. These pollutants are mutagenic, carcinogenic, immunotoxic and teratogenic for lower and higher forms of life i.e. microorganisms to humans. This review describes the sources of dioxins and furans pollution, hazardous effects on the ecosystem and recent techniques to minimize and treat dioxins and furans contaminants in the environment. This paper also previews the significance of conventional and latest remediation techniques prevailing around the globe for treating dioxins and furans entry into the ecosystem., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The understanding that enzymatic degradation of fruit pectin can clarify juices and improve juice yields resulted in the search for microbial pectinases and application in vegetable- and fruit-processing industries. Identified enzymes were classified on the basis of their catalytic activity to pectin or its derivatives and in terms of industrial use. Discovery of gene sequences that coded the enzymes, protein engineering, and molecular biology tools resulted in defined microbial strains that over-produced the enzymes for cost-effective technologies. Recent perspectives on the use of pectin and its derivatives as dietary fibers suggest enzymatic synthesis of the right oligomers from pectin for use in human nutrition. While summarizing the activities of pectin-degrading enzymes, their industrial applications, and gene sources, this review projects another application for pectinases, which is the use of enzymatically derived pectin moieties in functional food preparation.

A techno-economic analysis of submerged (SmF) and solid state fermentation (SSF) processes for Aspergillus carbonarius polygalacturonase production was performed to make an appropriate process selection. The downstream processing involved integrated membrane process (IMP) and alginate affinity precipitation (AAP). For a production scale of 30kL purified polygalacturonase concentrate per year, the total upstream cost of SmF was 14% lower than the SSF process. Downstream processing cost by IMP was 47% lower than AAP. The SmF-IMP process required a total capital investment that was 15-24% lower than the SmF-AAP and SSF-AAP processes. The corresponding unitary product cost was also lower by 24-36% in SmF-IMP process. Thus the SmF-IMP process proved to be very attractive from an economic point of view., (Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Aspergillus carbonarius, when grown by submerged and solid-state fermentation, produces different molecular forms of polygalacturonase (PG; EC 3.2.1.15), among them a 42 kDa PG with a high specific activity of 7000 U/mg protein. When the enzymes were purified by integrated membrane process (IMP) and alginate affinity precipitation (AAP), the two processes concentrated different forms of the enzyme. The AAP process selectively purified and concentrated the high active PG whereas the IMP yielded different PGs and also amylase and protease. Evaluation of the AAP enzyme preparations for apple juice preparation under conditions usually employed commercially demonstrated that the high activity PG did not result in good juice clarity. With IMP processed enzymes, juice yields and clarity were similar to that obtained with commercial PG from A. niger., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Purification of polygalacturonase (PG) from the cultures of Aspergillus carbonarius obtained by acetate buffer extraction after solid-state fermentation was attempted by integrated membrane process and alginate affinity precipitation. The carbohydrates were completely eliminated (98%-99%) with a PG recovery of 72%-80% during integrated membrane process, which would otherwise interfere with the purification process and lead to enzyme loss. However, specific activity of PG did not improve (1.19-1.21 fold) due to the presence of other similar molecular mass proteins. Under optimum conditions of affinity precipitation, the specific activity of PG enhanced to 2450 U/mg (4 fold) with almost complete elimination of carbohydrates and colour compounds resulting in a PG recovery of 61%. PG purity obtained with ultrafiltration (UF) was comparable with the conventional dialysis during desalting eluted PG, besides UF rendered a concentrated PG. The enzyme purity stated was as descend by SDS-PAGE. The results suggested suitability of affinity precipitation for PG purification from solid-state cultures and the potential of UF as a single step process for handling eluted PG., (Copyright (c) 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)