Nano fibrous carbon produced from chromium bearing tannery solid waste as the bitumen modifier.

Bitumen binders play a major role in reducing the aging and oxidation property of bitumen. Carbon nanomaterials act as an effective bitumen modifier due to its stiffness and strength. Thus, nano fibrous carbon (NFC) was prepared from Chrome Tanned Buffing Dust (a solidwaste generated from leather industries) with proper care of avoiding oxidation of Cr(III) to Cr(VI) through pulse pyrolysis system. Morphology analysis using TEM confirmed the nano fibrous structure of NFC. XRD pattern of NFC depicts the graphitic phases of carbon along with the Cr2O3. Prepared NFC has been used as bitumen modifier and the blending of NFC with bitumen were done using both conventional and microwave heating methods to study the proper blending methods to enhance the bitumen properties. Thermogram of the modified bitumen showed that the decomposition temperature increases by increasing the percentage of NFC (5-25%) in both the heating methods, but comparatively the thermal stability is more in microwave mixing than in conventional mixing. The morphology analysis of the modified bitumen showed that non-uniform blending in conventional type of heating and homogeneously blended mixture in microwave type of heating. The penetration value and ductility decreases while softening point and kinematic viscosity increases by increasing the quantity of NFC from 5 to 25% in modified bitumen. Microwave heat mixing method yielded better modified bitumen with NFC than conventional heating method in terms of stability, uniform blending and physical properties. The non-leachability of the Cr(III) in the NFC modified bitumen was confirmed through total chromium analysis in the leachate. But, chromium analysis in leachate of NFC immersed in acetate buffer for one month showed leaching of Cr(III) 5.5 µg/L in the 25% NFC modified bitumen block mixed using conventional heating method.

Antioxidant and antimicrobial activity of bioactive prodigiosin produces from Serratia marcescens using agricultural waste as a substrate.

The objective of this investigation was to explore the antioxidant and antimicrobial property of bioactive prodigiosin produced from Serratia marcescens using rice bran. The antioxidant potential of prodigiosin was examined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging method via UV-visible, electron spin resonance spectrum (ESR), cyclic voltammetry and excitation emission spectrum. The antimicrobial activity of prodigiosin was examined against foodborne pathogens. The shelf life extending capacity of prodigiosin was evaluated with meat extract powder (MEP) as a model food material. The DPPH and ABTS radicals were completely scavenged by prodigiosin at the concentration of 10 mg/L. The food spoilage was inhibited by the addition of prodigiosin with MEP and it was compared with conventional preservative. The prodigiosin has prohibited the growth of foodborne pathogens effectively and the shelf life of the food was also extended significantly. The antimicrobial edible preservative developed in this study inhibited the growth of the microbial populations that produced through storage of the MEP and free radical scavenging activity. The results reveal that the bioactive prodigiosin effectively scavenged the free radical and inhibited the bacterial growth in food stuff.

Anaerobic digestion of sulphate-rich post-tanning wastewater at different COD/sulphate and F/M ratios.

Anaerobic digestion of post-tanning wastewater was performed in batch anaerobic digester to evaluate the effect of COD/sulphate ratio [0.62, 0.69, and 1.20 (w/w) %] and F/M ratio [0.2, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3, and 1.5 (w/w) %)] on the removal efficiency of COD. The F/M ratio of 0.3 was found to be the optimum ratio for the removal of COD by 53, 57, and 65%, respectively at COD/sulphate ratio of 0.62, 0.69, and 1.20. The maximum sulphate removal was observed at F/M ratio of 0.2 and the removal efficiency was 48, 50, and 58% at COD/sulphate ratio of 0.62, 0.69, and 1.20, respectively. The removal efficiency of COD and sulphate was increased with increase in COD/sulphate ratio from 0.62 to 1.20 and decreased with increase in F/M ratio from 0.2 to 1.5 in anaerobic digestion of post-tanning wastewater. The maximum concentration of sulphide formation was 784 mg/L at COD/sulphate ratio of 0.62 in anaerobic digestion process and the process was inhibited at this sulphide concentration. The microbial activity in the sludge was evaluated through live and dead cell assay using fluorescent microscopy. The maximum amount of dead microbes was observed in the anaerobic digester, which was operated at COD/sulphate ratio of 0.62 than other studied ratio.

Synthesis of Surface-Modified Iron Oxides for the Solvent-Free Recovery of Bacterial Bioactive Compound Prodigiosin and Its Algicidal Activity.

Prodigiosin (PG) is a bioactive compound produced by several bacterial species. Currently, many technologies are being developed for the production of PG by fermentation processes. However, new challenges are being faced with regard to the production of PG in terms of the recovery and purification steps, owing to the labile nature of PG molecules and the cost of the purification steps. Conventional methods have limitations due to high cost, low reusability, and health hazards. Hence, the present investigation was focused on the development of surface-functionalized magnetic iron oxide ([Fe3O4]F) for solvent-free extraction of bioactive PG from the bacterial fermented medium. Fe3O4 was functionalized with diethanolamine and characterized by FT-IR, diffuse reflectance spectroscopy, thermogravimetric analysis, scanning electron microscopy, and confocal microscopy. The various process parameters, such as contact time, temperature, pH, and mass of Fe3O4, were optimized for the extraction of PG using functionalized Fe3O4. Instrumental analyses confirmed that the PG molecules were cross-linked with functional groups on [Fe3O4]F through van der Waals forces of attraction. PG extracted through Fe3O4 or [Fe3O4]F was separated from the fermentation medium by applying an external electromagnetic field and regenerated for successive reuse cycles. The purity of the extracted PG was characterized by high-performance liquid chromatography, FT-IR, and UV-visible spectroscopy. The iron oxide-diethanolamine-PG cross-linked ([Fe3O4]F-PG) composite matrix effectively deactivates harmful fouling by cyanobacterial growth in water-treatment plants. The present investigation provides the possibility of solvent-free extraction of bacterial bioactive PG from a fermented medium using functionalized magnetic iron oxide.

Production of prodigiosin using tannery fleshing and evaluating its pharmacological effects.

AIM: The focal theme of present investigation includes isolation of prodigiosin producing fish gut bacteria, enhancing its production using tannery solid waste fleshing, and evaluation of its pharmacological effect. METHODS: Optimization of fermentation conditions to yield maximum prodigiosin, and instrumental analysis using FTIR, NMR, ESI-MS, TGA, and DSC. RESULTS: The optimum conditions required for the maximum prodigiosin concentration were achieved at time 30 h, temperature 30°C, pH 8, and 3% substrate concentration. The secondary metabolite was analyzed using ESI-MS, FTIR, and NMR. Therapeutic efficacy was assessed by in vitro anticancer studies. Among the pathogenic bacteria Pseudomonas aeruginosa was most susceptible at the lowest concentration followed by Salmonella typhi. IC50 concentration was cell line specific (HeLa cells: 4.3 µM, HEp2: 5.2 µM, and KB cells: 4.8 µM) and remains nontoxic up to the concentration of 25 µM on normal Vero cells suggesting that cancerous cells are more susceptible to the prodigiosin at lower concentration. CONCLUSION: Maximum prodigiosin production was obtained with tannery fleshing. The potency of the fish gut bacterial secondary metabolite prodigiosin as a therapeutic agent was confirmed through in vitro antimicrobial and anticancer studies.

Nanoemulsion drug delivery by ketene based polyester synthesized using electron rich carbon/silica composite surface.

A new carrier matrix for nanoemulsion drug delivery was synthesized from glycine as the raw material, using mesoporous/microporous electron rich carbon-silica composite surface (MAC(800)). MAC(800) was prepared from rice husk in two-stage carbonization. The surface area, pore volume, and pore size distribution of MAC(800) were measured, using nitrogen adsorption isotherms at 77K. The unpaired electron density of MAC(800) was measured in electron spin resonance spectroscopy (ESR), using TEMPOL (4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl) as the reference spin probe. Glycine was converted into ketene at the surface of MAC(800), which further underwent radical polymerization to form a low molecular weight ketene polymer (LMKP) of ester structure. The structure and the properties of LMKP were confirmed through (13)C, (1)H and DEPT nuclear magnetic resonance (NMR) spectroscopy, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and size exclusion chromatography (SEC). The two hydrophilic drugs namely ciprofloxacin hydrochloride (CPH) and gentamicin sulphate (GS) were chosen for the nanoemulsion preparation and characterization. They were characterized for morphology, interaction of drugs with the polymer and their crystallinity, using HR-TEM, DSC and XRD, respectively. The encapsulation efficiency of the LMKP towards the drugs ciprofloxacin hydrochloride and gentamicin sulphate were 26% and 12%, respectively. The dissolution studies of the nanoemulsion were carried out for the pH 6.5, 7.4 and 8.0. The cytocompatibility studies were done for LMKP as well as nanoemulsion using Hep2 epithelial cells.

A novel amphiphilic nano hydrogel using ketene based polyester with polyacrylamide for controlled drug delivery system.

A ketene based Low molecular weight polymer (LMKP) having ester functional group was prepared using glycine through surface initiated anionic polymerization. NMR, ATR-FTIR & SEC were used to characterize the LMKP. The LMKP and acrylamide (AAm) were co-polymerised in methyl ethyl ketone to yield semi-IPN nanohydrogels (NHG). Benzoyl peroxide (BPO) was used as an initiator and N,N-methylene bisacrylamide (MBA) as crosslinking agent. Formation of NHG was confirmed through frequency shift in LMKP and poly acrylamide (PAAm) in FTIR spectroscopy. Photon correlation spectroscopy reveals that the sizes of the NHG were in the range of 140-225 nm and Transmission Electron Micrograph (TEM) also confirms the nano dimension of NHG. Biocompatibility of the NHG was confirmed through the cytotoxicity analysis. The swelling and diffusion behaviour of NHG, prepared under various formulations, were evaluated. The swelling pattern of NHG was studied at different pH conditions. The drug delivery capacity of NHG was investigated using ciprofloxacin as a model drug. The drug release kinetics of NHG suggested their anomalous (non-fickian) behaviour.

Characterization of an alkaline active-thiol forming extracellular serine keratinase by the newly isolated Bacillus pumilus.

AIMS: The aim of the study was to optimize microbial degradation of keratinous waste and to characterize the alkaline active keratinase showing its biotechnological importance. METHOD AND RESULTS: An extracellular keratinase enzyme was purified from the culture medium of a bacterial isolate and the conditions were optimized. The molecular weight of DEAE-Sepharose-purified keratinase was determined by SDS-PAGE. Instrumental analyses were investigated to study the mechanism of bovine hair hydrolysis. Isolate was identified as Bacillus pumilus based on phenotypic characteristics and 16S rDNA sequence. The optimized condition for its growth was pH 8 and 35 degrees C. The molecular weight of the keratinase was estimated as 65 kDa. Activity inhibition by phenyl methyl sulphonyl fluoride confirmed keratinase as serine protease type. Instrumental analysis revealed the sulphitolysis and proteolysis involved mechanism in bovine hair hydrolysis. CONCLUSION: This study indicates that the isolated keratinase is an alkaline active serine protease with a high degree of activity towards bovine hair. SIGNIFICANCE AND IMPACT OF THE STUDY: This study examines a serine protease with high keratinolytic activity and degradation mechanism for bovine hair. The keratinolytic activity of the isolated strain and its reaction mechanism on bovine hair could show biotechnological potential in the leather industry.

Safe disposal of toxic chrome buffing dust generated from leather industries.

The high concentration of trivalent chromium along with organic/inorganic compounds in chrome buffing dust (CBD), the solid waste discharged from leather industries, causes severe groundwater contamination on land co-disposal and chronic air pollution during thermal incineration. In the present investigation, CBD was subjected to starved air incineration (SAI) at 800 degrees C in a thermal incinerator under different flow rates of oxygen to optimize the oxygen required to incinerate the organic compounds and simultaneously preventing the conversion of Cr(3+) to Cr(6+). The energy audit of SAI of buffing dust under the external supply of oxygen was carried out under different incineration conditions. The bottom ash from SAI was effectively solidified/stabilized using Portland cement and fine aggregate. The solidified blocks were tested for unconfined compressive strength and heavy metal leaching. Unconfined compressive strength of the blocks was in the range of 120-180 kg/cm(2). The stabilization of chromium(III) in the cement gel matrix was confirmed using Scanning Electron Microscopy SEM, Electron Paramagnetic Resonance spectroscopy (EPR) and X-ray diffraction spectroscopy (XRD). Leachability studies through TCLP on solidified blocks were carried out to determine the degree of leaching of chromium and organic compounds (expressed as COD) under standard conditions.

Production of alkaline protease by Pseudomonas aeruginosa using proteinaceous solid waste generated from leather manufacturing industries.

Animal fleshing (ANFL), the major proteinaceous solid waste discharged from leather manufacturing industries was used as the substrate for the production of alkaline protease by Pseudomonas aeruginosa. The strain isolated from the tannery wastewater was selected for its ability to produce protease of activity in the range 1160-1175 U ml(-1). The selective removal of non-fibrillar proteins such as albumin and globulin from ANFL by the protease enzyme during the progress of hydrolysis was confirmed using scanning electron microscopy (SEM). The breakdown of ANFL was also confirmed from the amino acid release into the fermentation medium by P. aeruginosa using high performance liquid chromatography (HPLC).

Starved air combustion-solidification/stabilization of primary chemical sludge from a tannery.

The high concentration of trivalent chromium along with organic/inorganic compounds in tannery sludge causes severe ground water contamination in the case of land disposal and chronic air pollution during incineration. In the present investigation, the sludge was subjected to flow-through column test to evaluate the concentration of leachable organics (tannin, COD and TOC) and heavy metal ions (Cr(3+), Fe(2+)) present in it. The dried sludge was incinerated at 800 degrees C in an incinerator under starved oxygen supply (starved-air combustion) to prevent the conversion of Cr(3+) to Cr(6+). The efficiency of starved air combustion was studied under different loading rates of sludge. The calcined sludge was solidified/stabilized using fly ash and Portland cement/gypsum. The solidified bricks were tested for unconfined compressive strength and heavy metal leaching. Unconfined compressive strength of the blocks was in the range of 83-156 kg/cm(2). The stabilization of chromium (III) in the cement gel matrix was confirmed with scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDX). Leachability studies on solidified bricks were carried out to determine the metal fixation and dissolved organic (as COD) concentration in the leachate.

Air pollution in stone crushing industry, and associated health effects.

Stone crushers are small scale industries in the unorganised sector. They provide basic material for road and building construction. They are highly labour intensive. The various unit operations involved in stone crushing viz., size reduction, size classification and transfer operations have the potential to emit process and fugitive dust. A detailed air pollution survey was conducted at Pammal, 26 km to the southwest of Chennai. High volume and respirable particulate samplers were deployed at seventeen locations to monitor SPM and PM10 levels in ambient air. The particle size analysis indicates high percentage of finer particles and silica content posing serious health problems to the people exposed for longer duration. Personal samplers were employed to quantify the total dust and respirable particulate fraction in the work environment, which was found significantly high, when compared to the occupational safety and health standards. Fine inhalable particulate matter (PM2.5) which has more associated human health problems was found high in the work place of stone crushers. Health survey viz., Pulmonary function test, blood sample test, general clinical evaluation was conducted to assess the extent of the damage caused to the workers. This study indicates that most of the people are having respiratory problems. The measurements show that good house keeping practice is essential for effective control of dust, in addition to National Productive Council's (NPC) measures.