Rijuta Ganesh Saratale

Enhanced decolorization and biodegradation of textile azo dye Scarlet R by using developed microbial consortium-GR

A developed consortium-GR, consisting of Proteus vulgaris NCIM-2027 (PV) and Micrococcus glutamicus NCIM-2168 (MG), completely decolorized an azo dye Scarlet R under static anoxic condition with an average decolorization rate of 16,666 microg h(-1); which is much faster than that of the pure cultures (PV, 3571 microg h(-1); MG, 2500 microg h(-1)). Consortium-GR gave best decolorization performance with nearly complete mineralization of Scarlet R (over 90% TOC and COD reduction) within 3h, much shorter relative to the individual strains. Induction in the riboflavin reductase and NADH-DCIP reductase was observed in the consortium, suggesting the involvement of these enzymes during the fast decolorization process. The FTIR and GC-MS analysis showed that 1,4-benzenediamine was formed during decolorization/degradation of Scarlet R by consortium-GR. Phytotoxicity studies revealed no toxicity of the biodegraded products of Scarlet R by consortium-GR. In addition, consortium-GR applied for mixture of industrial dyes showed 88% decolorization under static condition with significant reduction in TOC (62%) and COD (68%) within 72 h, suggesting potential application of this microbial consortium in bioremediation of dye-containing wastewater.

Ecofriendly degradation of sulfonated diazo dye C.I. Reactive Green 19A using Micrococcus glutamicus NCIM-2168

Micrococcus glutamicus NCIM-2168 exhibited complete decolorization and degradation of C.I. Reactive Green 19A (an initial concentration of 50 mg l(-1)) within 42 h at temperature 37 degrees C and pH 8, under static condition. Extent of mineralization was determined with total organic carbon (TOC) and chemical oxygen demand (COD) measurement, showing a satisfactory reduction of TOC (72%) and COD (66%) within 42 h. Enzyme studies shows involvement of oxidoreductive enzymes in decolorization/degradation process. Analytical studies of the extracted metabolites confirmed the significant degradation of Reactive Green 19A into various metabolites. The microbial toxicity and phytotoxicity assay revealed that the degradation of Reactive Green 19A produced nontoxic metabolites. In addition, the M. glutamicus strain was applied to decolorize a mixture of ten reactive dyes showing a 63% decolorization (in terms of decrease in ADMI value) within 72 h, along with 48% and 42% reduction in TOC and COD under static condition.

Multicomponent cellulase production by Cellulomonas biazotea NCIM-2550 and its applications for cellulosic biohydrogen production.

Among four cellulolytic microorganisms examined, Cellulomonas biazotea NCIM‐2550 can grow on various cellulosic substrates and produce reducing sugar. The activity of cellulases (endoglucanase, exoglucanase, and cellobiase), xylanase, amylase, and lignin class of enzymes produced by C. biazotea was mainly present extracellularly and the enzyme production was dependent on cellulosic substrates (carboxymethyl cellulose [CMC], sugarcane bagasse [SCB], and xylan) used for growth. Effects of physicochemical conditions on cellulolytic enzyme production were systematically investigated. Using MnCl2 as a metal additive significantly induces the cellulase enzyme system, resulting in more reducing sugar production. The efficiency of fermentative conversion of the hydrolyzed SCB and xylan into clean H2 energy was examined with seven H2‐producing pure bacterial isolates. Only Clostridiumbutyricum CGS5 exhibited efficient H2 production performance with the hydrolysate of SCB and xylan. The cumulative H2 production and H2 yield from using bagasse hydrolysate (initial reducing sugar concentration = 1.545 g/L) were approximately 72.61 mL/L and 2.13 mmol H2/g reducing sugar (or 1.91 mmol H2/g cellulose), respectively. Using xylan hydrolysate (initial reducing sugar concentration = 0.345 g/L) as substrate could also attain a cumulative H2 production and H2 yield of 87.02 mL/L and 5.03 mmol H2/g reducing sugar (or 4.01 mmol H2/g cellulose), respectively.

A review on bio-electrochemical systems (BESs) for the syngas and value added biochemicals production

Bio-electrochemical systems (BESs) are the microbial systems which are employed to produce electricity directly from organic wastes along with some valuable chemicals production such as medium chain fatty acids; acetate, butyrate and alcohols. In this review, recent updates about value-added chemicals production concomitantly with the production of gaseous fuels like hydrogen and methane which are considered as cleaner for the environment have been addressed. Additionally, the bottlenecks associated with the conversion rates, lower yields and other aspects have been mentioned. In spite of its infant stage development, this would be the future trend of energy, biochemicals and electricity production in greener and cleaner pathway with the win-win situation of organic waste remediation. Henceforth, this review intends to summarise and foster the progress made in the BESs and discusses its challenges and outlook on future research advances.

A comprehensive overview on electro-active biofilms, role of exo-electrogens and their microbial niches in microbial fuel cells (MFCs)

Microbial fuel cells (MFCs) are biocatalyzed systems which can drive electrical energy by directly converting chemical energy using microbial biocatalyst and are considered as one of the important propitious technologies for sustainable energy production. Much research on MFCs experiments is under way with great potential to become an alternative to produce clean energy from renewable waste. MFCs have been one of the most promising technologies for generating clean energy industry in the future. This article summarizes the important findings in electro-active biofilm formation and the role of exo-electrogens in electron transfer in MFCs. This study provides and brings special attention on the effects of various operating and biological parameters on the biofilm formation in MFCs. In addition, it also highlights the significance of different molecular techniques used in the microbial community analysis of electro-active biofilm. It reviews the challenges as well as the emerging opportunities required to develop MFCs at commercial level, electro-active biofilms and to understand potential application of microbiological niches are also depicted. Thus, this review is believed to widen the efforts towards the development of electro-active biofilm and will provide the research directions to overcome energy and environmental challenges.

Oxidative stress response in dye degrading bacterium Lysinibacillus sp. RGS exposed to Reactive Orange 16, degradation of RO16 and evaluation of toxicity

Lysinibacillus sp. RGS degrades sulfonated azo dye Reactive Orange 16 (RO16) efficiently. Superoxide dismutase and catalase activity were tested to study the response of Lysinibacillus sp. RGS to the oxidative stress generated by RO16. The results demonstrated that oxidative stress enzymes not only protect the cell from oxidative stress but also has a probable role in decolorization along with an involvement of oxidoreductive enzymes. Formation of three different metabolites after degradation of RO16 has been confirmed by GC-MS analysis. FTIR analysis verified the degradation of functional groups of RO16, and HPTLC confirmed the removal of auxochrome group from the RO16 after degradation. Toxicity studies confirmed the genotoxic, cytotoxic, and phytotoxic nature of RO16 and the formation of less toxic products after the treatment of Lysinibacillus sp. RGS. Therefore, Lysinibacillus sp. RGS has a better perspective of bioremediation for textile wastewater treatment.

Biohydrogen from Renewable Resources

Abstract The world’s energy markets rely heavily on fossil fuels (such as coal, petroleum, and natural gases). However, due to increasing energy demands, depleting reserves of fossil fuels, and increasing negative effects on the environment (e.g., global warming and climate changes), as well as growing political instability in oil-producing nations, the world is facing a major energy threat that needs to be solved by virtue of alternative energy sources utilizing renewable resources. The only natural, renewable carbon resource known with large enough capacity to substitute for fossil fuels is biomass. Thus, energy from biomass is considered to be one of the most promising alternatives to fossil fuels. Among the existing biomass energy/biofuels, biohydrogen has received considerable attention as it is clean, renewable, has a high energy content, and does not contribute to the greenhouse effect. Biomass is projected as a virtually eternal raw material for hydrogen (H2) production; however, the main bottleneck is the low hydrogen yield arising from poor efficiency on direct microbial assimilation of biomass. Therefore, technologies leading to more efficient and commercially viable production of biohydrogen from biomass and other renewable resources are urgently demanded. This chapter sheds light on some of the practical approaches of fermentative H2-generating processes utilizing a variety of biomass and renewable resources as substrate. This chapter also emphasizes biohydrogen production technology that could maximize hydrogen yield by designing efficient bioprocess integration and energy and waste minimization. Improving the hydrolysis of biomass has been recognized as a key step toward biohydrogen production. Considerable research efforts made on improving the pretreatment and hydrolysis of biomass materials are also addressed. Emphasis is given to discussion of the process based on important operating factors involved and to delineation of some of the process limitations. The aim of this chapter is to provide rapidly expanding information on biohydrogen production from renewable resources and to offer clues and possibilities for enhancing the performance of natural waste utilization and dark fermentative hydrogen production to resolve issues related to food security, climate change, energy security, and clean development in the future.

Bioelectrochemical systems using microalgae – A concise research update

Excess consumption of energy by humans is compounded by environmental pollution, the greenhouse effect and climate change impacts. Current developments in the use of algae for bioenergy production offer several advantages. Algal biomass is hence considered a new bio-material which holds the promise to fulfil the rising demand for energy. Microalgae are used in effluents treatment, bioenergy production, high value added products synthesis and CO2 capture. This review summarizes the potential applications of algae in bioelectrochemically mediated oxidation reactions in fully biotic microbial fuel cells for power generation and removal of unwanted nutrients. In addition, this review highlights the recent developments directed towards developing different types of microalgae MFCs. The different process factors affecting the performance of microalgae MFC system and some technological bottlenecks are also addressed.

Exploiting antidiabetic activity of silver nanoparticles synthesized using Punica granatum leaves and anticancer potential against human liver cancer cells (HepG2)

Abstract This study first time reports the novel synthesis of silver nanoparticles (AgNPs) using a Punica granatum leaf extract (PGE). The synthesized AgNPs were characterized by various analytical techniques including UV–Vis, Fourier transform infrared (FTIR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy and energy-dispersive spectra (FESEM-EDS) and high-resolution transmission electron microscopy (HRTEM). FTIR analysis revealed that the involvement of biological macromolecules of P. granatum leaf extract were distributed and involved in the synthesis and stabilization of AgNPs. A surface-sensitive technique of XPS was used to analyse the composition and oxidation state of synthesized AgNPs. The analytical results confirmed that the AgNPs were crystalline in nature with spherical shape. The zeta potential study revealed that the surface charge of synthesized AgNPs was highly negative (−26.6 mV) and particle size distribution was ranging from ∼35 to 60 nm and the average particle size was about 48 nm determined by dynamic light scattering (DLS). The PGE-AgNPs antidiabetic potential exhibited effective inhibition against α-amylase and α-glucosidase (IC50; 65.2 and 53.8 μg/mL, respectively). The PGE-AgNPs showed a dose-dependent response against human liver cancer cells (HepG2) (IC50; 70 μg/mL) indicating its greater efficacy in killing cancer cells. They also possessed in vitro free radical-scavenging activity in terms of ABTS (IC50; 52.2 μg/mL) and DPPH (IC50; 67.1 μg/mL) antioxidant activity. PGE-AgNPs displayed strong antibacterial activity and potent synergy with standard antibiotics against pathogenic bacteria. Thus, synthesized PGE-AgNPs show potential biomedical and industrial applications.

Synthesis and characterization of silver nanoparticles using Gelidium amansii and its antimicrobial property against various pathogenic bacteria

Microfouling is evolving at a fast rate causing augmented mortality rates and damage worldwide. Until now, several remedial measures have been exploited to overcome microfouling, amongst them nanoparticles play a superior role. Currently, green synthesized nanoparticles have been centered owing to its eco-friendly, cost effectively and non-toxic nature which has also increased its industrial applications (biomedicine, food and textile). In the present research Silver Nanoparticles (Ag NPs) synthesized using marine red algae Gelidium amansii. The synthesized Ag NPs were characterized using UV-Vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Further the antibacterial potentials of Ag NPs were evaluated against pathogenic Gram positive (Staphylococcus aureus, Bacillus pumilus) and Gram negative bacterial (Escherichia coli, Pseudomonas aeruginosa, Vibrio parahaemolyticus, Aeromonas hydrophila) pathogens. Our findings suggest that Ag NPs synthesized using a green approach effectively reduce the bacterial growth by eliciting a bactericidal activity against the Gram Negative and Gram Positive biofilm forming pathogens. Thereby, Ag NPs synthesized using G. amansii could reflect as potential anti micro-fouling coatings for various biomedical and environmental applications.