Cellulose-based water filters are an affordable alternative to remove particulate matter; however, bacteria are too small to be removed simply through size exclusion. Cellulose-based water filters ...prepared by layer-by-layer (LBL) assembly with polypropylene-polyethylene (PP/PE) fabric decorated with silver nanoparticles (AgNPs) were tested to remove bacteria from water samples. The gallic acid reduction method was used to produce potent antibacterial AgNPs; their decoration onto PP/PE woven fabrics and the preparation of five-layered paper filters were further investigated. The use of acidic conditions for loading AgNPs and improving their spatial distribution onto the PP/PE fabrics, as revealed by scanning electron microscopy, was found to be correlated with the fabrics’ antibacterial activity. The PP/PE fabrics decorated with a higher density of AgNPs (at pH 2) showed 96.7 % and 97.9 % reductions in the growth of
E. coli
and
S. aureus
, respectively. Similarly, paper filters fabricated by LBL assembly of AgNP@PP/PE fabrics with cellulose filters deactivated growing
E. coli
and
S. aureus
bacteria with good efficiency: approximately 99.4 % and 98.7 %, respectively. The results indicate that fabricating water purification filters from the cellulose-based paper is feasible with LBL type assembly. The assembled paper filters could be commercialized for point-of-use water purification in the future to prevent the spread of water-borne diseases.
The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital ...for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.
This study focuses on the development of a nanosupport based on halloysite nanotubes (HNTs), Fe
O
nanoparticles (NPs), and thiolated chitosan (CTs) for laccase immobilization. First, HNTs were ...modified with Fe
O
NPs (HNTs-Fe
O
) by the coprecipitation method. Then, the HNTs-Fe
O
surface was tuned with the CTs (HNTs-Fe
O
-CTs) by a simple refluxing method. Finally, the HNTs- Fe
O
-CTs surface was thiolated (-SH) (denoted as; HNTs- Fe
O
-CTs-SH) by using the reactive NHS-ester reaction. The thiol-modified HNTs (HNTs- Fe
O
-CTs-SH) were characterized by FE-SEM, HR-TEM, XPS, XRD, FT-IR, and VSM analyses. The HNTs-Fe
O
-CTs-SH was applied for the laccase immobilization. It gave excellent immobilization of laccase with 100% activity recovery and 144 mg/g laccase loading capacity. The immobilized laccase on HNTs-Fe
O
-CTs-SH (HNTs-Fe
O
-CTs-S-S-Laccase) exhibited enhanced biocatalytic performance with improved thermal, storage, and pH stabilities. HNTs-Fe
O
-CTs-S-S-Laccase gave outstanding repeated cycle capability, at the end of the 15th cycle, it kept 61% of the laccase activity. Furthermore, HNTs-Fe
O
-CTs-S-S-Laccase was applied for redox-mediated removal of textile dye DR80 and pharmaceutical compound ampicillin. The obtained result marked the potential of the HNTs-Fe
O
-CTs-S-S-Laccase for the removal of hazardous pollutants. This nanosupport is based on clay mineral HNTs, made from low-cost biopolymer CTs, super-magnetic in nature, and can be applied in laccase-based decontamination of environmental pollutants. This study also gave excellent material HNTs-Fe
O
-CTs-SH for other enzyme immobilization processes.
In the current scenario of changing climatic conditions and the rising global population, there is an urgent need to explore novel, efficient, and economical natural products for the benefit of ...humankind. Biosurfactants are one of the latest explored microbial synthesized biomolecules that have been used in numerous fields, including agriculture, pharmaceuticals, cosmetics, food processing, and environment-cleaning industries, as a source of raw materials, for the lubrication, wetting, foaming, emulsions formulations, and as stabilizing dispersions. The amphiphilic nature of biosurfactants have shown to be a great advantage, distributing themselves into two immiscible surfaces by reducing the interfacial surface tension and increasing the solubility of hydrophobic compounds. Furthermore, their eco-friendly nature, low or even no toxic nature, durability at higher temperatures, and ability to withstand a wide range of pH fluctuations make microbial surfactants preferable compared to their chemical counterparts. Additionally, biosurfactants can obviate the oxidation flow by eliciting antioxidant properties, antimicrobial and anticancer activities, and drug delivery systems, further broadening their applicability in the food and pharmaceutical industries. Nowadays, biosurfactants have been broadly utilized to improve the soil quality by improving the concentration of trace elements and have either been mixed with pesticides or applied singly on the plant surfaces for plant disease management. In the present review, we summarize the latest research on microbial synthesized biosurfactant compounds, the limiting factors of biosurfactant production, their application in improving soil quality and plant disease management, and their use as antioxidant or antimicrobial compounds in the pharmaceutical industries.
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•Macroalgae-based galactose can be harnessed as substrate for hydrogen synthesis.•Galactose-to-H2 by fermentation is highly successful at academic research level.•Hydrogen from ...galactose by fermentation holds promise as a source of bioenergy.•Process intensification of galactose-to-H2 fermentation is a current challenge.•Supply chain for macroalgae-based galactose-to-H2 needs in-depth analysis.
This review analyses the relevant studies which focused on hydrogen synthesis by dark fermentation of galactose from macroalgal biomass by discussing the inoculum-related pretreatments, batch fermentation and inhibition, continuous fermentation systems, bioreactor designs for continuous operation and ionic liquid-assisted catalysis. The potential for process development is also revisited and the challenges towards suppressing glucose dominance over a galactose-based hydrogen production system are presented. The key challenges in the pretreatment process aiming to achieve a maximum recovery of upgradable (fermentable) sugars from the hydrolysates and promoting the concomitant detoxification of the hydrolysates have also been highlighted. The research avenues for bioprocess intensification connected to enhance selective sugar recovery and effective detoxification constitute the critical steps to develop future red macroalgae-derived galactose-based robust biohydrogen production system.
In nanoscience, the "green" synthesis approach has received great interest as an eco-friendly and sustainable method for the fabrication of a wide array of nanoparticles. The present study accounts ...for an expeditious technique for the synthesis of silver nanoparticles (AgNPs) utilizing fruit waste grape pomace extracted tannin. Grape pomace tannin (Ta) involved in the reduction and capping of AgNPs and leads to the formation of stable Ta-AgNPs. Various conditions were attempted to optimize the particle size and morphology of Ta-AgNPs which was further analyzed using various analytical tools for different characteristic motives. UV-visible spectroscopy showed a characteristic peak at 420 nm, indicating successful synthesis of AgNPs. Energy disperses spectroscopy (EDS) analysis proved the purity of the produced Ta-AgNPs and manifested a strong signal at -2.98 keV, while Fourier-transform infrared spectrophotometer (FTIR) spectra of the Ta-AgNPs displayed the existence of functional groups of tannin. Zeta potential measurements (-28.48 mV) showed that the Ta-AgNPs have reasonably good stability. High resolution transmission electron microscopy (HR-TEM) analysis confirmed the average dimension of the synthesized NPs was estimated about 15-20 nm. Ta-AgNPs potentials were confirmed by in vitro antidiabetic activity to constrain carbohydrate digesting enzymes, mainly α-amylase and α-glucosidase, with a definite concentration of sample displaying 50% inhibition (IC
), which is about 43.94 and 48.5 μg/mL, respectively. Synthesized Ta-AgNPs exhibited significant antioxidant potential with respect to its 2,2'-azino-bis(3-ethylbenzothi-azoline-6-sulfonic acid) (ABTS) (IC
of 40.98 µg/mL) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC
of 53.98 µg/mL) free radical scavenging activities. Ta-AgNPs exhibited extraordinary antibacterial activity against selected pathogenic strains and showed comparable antimicrobial index against ampicillin as a positive control.
The potential of isolated actinomycetes and fungi were evaluated for the cellulase and xylanase production under solid state fermentation conditions. Maximal secretion of enzymes was observed with ...Phanerochaete chrysosporium using soybean straw. The potential of the produced crude enzyme complex was demonstrated by two-step enzymatic hydrolysis of untreated and mild acidpretreated sorghum husk (SH). A cellulase dose of 10 filter paper units (FPU) released 563.21 mg of reducing sugar (RS) per gram of SH with 84.45% hydrolysis and 53.64% glucose yields, respectively. Finally, enzymatic hydrolysates of SH were utilized for hydrogen production by Clostridium beijerinckii. Effects of temperature, pH of media, and substrate concentration on the biohydrogen production from SH hydrolysates were investigated. The optimal conditions for maximal hydrogen production using SH hydrolysate were determined to be a loading of 5.0 g RS/L, at 35°C, and controlled pH at 5.5. Under these optimal conditions, the cumulative H₂ production, H₂ production rate, and H₂ yield were 1,117 mL/L, 46.54 mL/L/h, and 1.051 mol/mol RS, respectively. These results demonstrated a cost-effective hydrogen production is possible with sorghum husk as a lignocellulosic feedstock.
Proteus vulgaris NCIM-2027 cells immobilized on
Luffa cylindrica (Loofa) completely decolorized C.I. Reactive Blue 172 at 37 °C and pH 8.0 under 5-h static incubation with high total organic carbon ...(TOC) and chemical oxygen demand (COD) reduction. The repeated-batch decolorization experiments also indicate good reusability of the immobilized biocatalyst. Some oxidoreductive enzymes were shown to be involved in the decolorization and degradation process. Loofa immobilized cells were also able to decolorize a mixture of reactive dyes in batch mode (in terms of ADMI value) with significant reduction in TOC and COD. Loofa immobilized cells were also used for continuous decolorization of individual and mixture of reactive dyes in a fixed bed bioreactor.
Grape pomace, a most abundant and renewable wine industry waste product was utilized as a suitable reducing, capping, and stabilizing biomolecules for green synthesis of silver nanoparticles (AgNPs). ...The physicochemical properties of biosynthesized grape pomace extract (GPE)-AgNPs were duly appraised via UV–Visible spectroscopy, X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy. The analytical studies revealed that the GPE-AgNPs were well formed and stable in nature. The functional groups of organic molecules of GPE are present on the surface of AgNPs with average NPs diameter in the range of 20–35 nm. GPE-AgNPs exhibited significant free radical scavenging activity mainly DPPH radical (IC50, 50.0 ± 2.25 μg/mL) and ABTS radical (IC50, 38.46 ± 1.14 μg/mL). Additionally, the synthesized AgNPs showed noticeable inhibition of carbohydrate hydrolyzing enzymes mainly, α-amylase (IC50, 60.2 ± 2.15 μg/mL) and α-glucosidase (IC50, 62.5 ± 2.75 μg/mL). The GPE fabricated AgNPs showed noteworthy antibacterial potential against infectious bacteria viz., Escherichia coli and Staphylococcus aureus. The reaction mechanism of antibacterial activity was studied by measuring the bacterial cell membrane breakage and cytoplasmic contents, mainly, nucleic acid, proteins, and reducing sugar. Therefore, this research attempt illustrated the potential of GPE as a novel source intended for the biosynthesis of AgNPs that may open up new horizons in the field of nanomedicine.
This study aims to utilize a noxious weed water hyacinth biomass (WH) for polyhydroxybutyrate (PHB) production. Alkaline and peracetic acid pretreatment was employed for the hydrolysis of WH and ...consequently enzymatic saccharification to produce fermentable sugars for PHB production. The pretreatment competence was determined using various operational parameters. By applying ambient conditions, alkaline pretreatment gave higher lignin removal of 65.0%, with 80.8% hydrolysis yield, and on enzyme hydrolysis (40 FPU/g of dry WH), produced total reducing sugar of about 523 mg/g of WH. The resulted WH enzymatic hydolysates were evaluated for the production of PHB by Ralstonia eutropha (ATCC 17699). The WH hydrolysates cultivation was compared to synthetic hydrolysates that contain a similar carbon composition in terms of bacterial growth and PHB synthesis. The effects of various supplements to enhance PHB production were estimated. Supplementation of corn steep liquor (CSL) as a cheap nitrogen source with WH hydrolysates favored a higher amount of PHB synthesis (73%), PHB titer of 7.30 g/L and PHB yield of 0.429 g/g of reducing sugar. Finally, using standard analytical tools, the physical and thermal characteristics of the extracted PHB were evaluated. The findings revealed WH was a promising and technically feasible option for transforming biomass into sustainable biopolymer conversion on a large scale.
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