Degradation of reactive red 195 by selected bacteria from textile wastewater

Four selected bacterial strains coded R1, R2, Rc and Rd were successfully isolated from raw textile wastewater. They were screened for their ability to degrade an azo dye of Reactive Red 195 on solid and in liquid dye-containing media. Screening showed that decolourization was best performed under anaerobic condition with the highest colour removal (˜70%) showed by bacterium R2. The partial 16S ribosomal ribonucleic acid (16S rRNA) sequence of bacterium R2 shared 98% sequence similarity to Paenibacillus sp.. Decolourization by this bacterium in a chemically defined medium containing (gL-1) of glucose (1), NH4Cl (0.5), K2HPO4 (7), KH2PO4 (2), MgSO4.7H2O (0.1), CaCl2 (0.02), and Reactive red 195 (0.1), adjusted to pH7 and with (10% v/v) inoculum occurred under partial anaerobic condition at temperature of 37°C. Under optimized condition, bacterium R2 successfully removed more than 95% colour and up to 50% of total organic carbon. No significant change in pH was observed (pH from 7.21 to 7.25) though the anaerobiosis was found to be developed throughout the experiment (redox potential reduced from 2.5 to 0.5 mV). This bacterium produced intracellular (0.033 U/mL) and extracellular (0.026 U/mL) azoreductase enzymes which were found to be stable at pH from 6 to 8 and temperature ranging from 30 ºC to 40ºC. High performance liquid chromatography analysis revealed that biodegradation of Reactive Red 195 under partial anaerobic condition produced at least three types of sulfonated amines which were 4-aminobenzenesulphonic acid (sulphanilic acid), 4-amino-3- hydronapthalenesulphonic acid and 4-amino-5-hydronapthalene-2,7disulphonic acid. The sulphanilic acid can be further degraded to a-ketoglutaric acid, a common Krebs cycle’s intermediate in most aerobic microorganism. Therefore, it can be concluded that the Paenibacillus sp. is of good potential use for the treatment of azo dye-containing wastewater based on its ability to remove colour

Rhizofiltration of water contaminated with heavy metal using impatiens balsamina plant / Syazuani Mohd Shariff … [et al.]

The Earth is poised at the brink of a severe environmental crisis. Current environmental problems make its living communities vulnerable to disasters and tragedies in future ongoing. The changes in the environment has urged public to increase their awareness towards the problems that surround it. All across the world, pollution issue has become one of the critical environmental problems especially in developed and developing countries. Pollution of air, water and soil required millions of years to recoup. Human activities responsible for the pollution directly, meanwhile fertilization activities in agricultural farming caused the leaching process of abundance of concentrated essential nutrients in the soil. Excessive production amount of waste from industrial activities without proper disposal ethic and mechanism also contributed to the mobilization of hazardous contaminants thoroughly from soil to the underground water supply. Due to the increasing accumulation of heavy metals in the underground environment, it has urged scientists to come out with new technologies to restraint and/or reduce the toxicity level of contaminant substances in the polluted aquatic environment. This is a very challenging job with respect to cost and technical complexity (Barcelo and Poschenrieder, 2003). In fact, the introduced conventional method in cleaning the polluted aquatic sites such as in situ vitrification, microfiltration and sedimentation techniques, solidification, and stabilization of electro-kinetic systems suffer from limitations, such as costly, intensive labor, irreversible changes in physico-chemical properties in aqueous and disturbance of native micro-flora, hence potentially create secondary pollution problems (Sheoran et al., 2011). Since the conventional method mostly proved to be partially effective in decontaminating hazardous heavy metals in the environment, researchers have came out with a variety of biological sources that have been employed widely in developed and developing nations for the cleanup approaches. The basic idea of exploiting plants ability to decontaminate polluted sites has gained considerable momentum in early 1900's, when scientist from Soviet Union develop the concept of geobotany, known as the study of plants ability to grow dependence on environment (Rawat et al., 2012)

Antioxidant Potential of Chloranthus erectus (Chloranthaceae) from various solvents extract

Chloranthus erectus is a herbaceous plant that has been used as a medicinal plant in several regions such as China and Southeast Asia. Although it possesses valuable medicinal properties, till now there is not much research has been carried out on the medicinal properties of this plant and the knowledge of this plant is limited among the research fertility. Therefore, this study aimed to identify the phytochemicals, total phenolic content (TPC), and antioxidant activity of leaf and twig of C. erectus in various solvents extract (hexane, petroleum ether, chloroform, ethyl acetate, and methanol). Phytochemical screening of extracts showed the presence of alkaloids, flavonoids, terpenoids, saponins, quinones, glycosides, and steroids. The highest phenolic content for leaf and twig samples was determined from the methanolic (9.64 ± 0.15 µg GAE/g) and hexanoic extract (7.39 ± 0.27 µg GAE/g), respectively. Meanwhile, the highest antioxidant activity was reported from the methanolic extract of both leaf (88.36 ± 0.24%) and twig (91.25 ± 0.10%) samples. Hence, the results of the study can be concluded that C. erectus has the potential to become a good natural antioxidant and the information from this study can be utilized by the communities as well as other researchers

Antimicrobial activity of nigella sativa seed extract

Pathogenic bacterial infections have become a major health problem worldwide. New antimicrobial agents are urgently needed to overcome this problem. In this study, antibacterial activity of Nigella sativa seed extract against some pathogenic bacterial strains (Streptococcus pyogene, Pseudomonas aeruginosa, Klebseilla pneumoniae and Proteus vulgaris) was evaluated. Methanol extract at the concentration of 100 mg/mL had a remarkable sensitivity towards all tested bacteria in this study. Klebseila pneumonia and Proteus vulgaris showed resistance against aqueous extract at 20 mg/mL. Methanol extract of Nigella sativa exhibited significant antibacterial activity at the concentration of 50 mg/mL (p ≤ 0.01) against Streptococcus pyogenes with a greater inhibition zone of 19 mm, while a 15 mm zone of inhibition was observed in Pseudomonas aeruginosa, pneumonia and Proteus vulgaris. Kruskal Wallis analysis showed that both aqueous and methanol extract of black seed exhibited a greater inhibition on Gram positive bacteria (Streptococcus pyogenes) compared with Gram negative bacteria (Pseudomonas aeruginosa, Klebseilla pneumoniae and Proteus vulgaris). Our study also showed that species, strains and concentrations of Nigella sativa extract are some of the factors that may influence the sensitivity of the tested bacteria. A significant correlation was observed between zone of inhibition and concentration of extract

The effect of hydraulic retention time on granular sludge biomass in treating textile wastewater

The physical characteristics, microbial activities and kinetic properties of the granular sludge biomass were investigated under the influence of different hydraulic retention times (HRT) along with the performance of the system in removal of color and COD of synthetic textile wastewater. The study was conducted in a column reactor operated according to a sequential batch reactor with a sequence of anaerobic and aerobic reaction phases. Six stages of different HRTs and different anaerobic and aerobic reaction time were evaluated. It was observed that the increase in HRT resulted in the reduction of organic loading rate (OLR). This has caused a decrease in biomass concentration (MLSS), reduction in mean size of the granules, lowered the settling ability of the granules and reduction of oxygen uptake rate (OUR), overall specific biomass growth rate (ì overall), endogeneous decay rate (k d) and biomass yield (Y obs, Y). When the OLR was increased by adding carbon sources (glucose, sodium acetate and ethanol), there was a slight increase in the MLSS, the granules mean size, ì overall, and biomass yield. Under high HRT, increasing the anaerobic to aerobic reaction time ratio caused an increase in the concentration of MLSS, mean size of granules and lowered the SVI value and biomass yield. The ì overall and biomass yield increased with the reduction in anaerobic/aerobic time ratio. The HRT of 24 h with anaerobic and aerobic reaction time of 17.8 and 5.8 h respectively appear to be the best cycle operation of SBR. Under these conditions, not only the physical properties of the biogranules have improved, the highest removal of color (i.e. 94.1 ± 0.6%) and organics (i.e. 86.5 ± 0.5%) of the synthetic textile dyeing wastewater have been achieved

Development of granular sludge for textile wastewater treatment

Microbial granular sludge that is capable to treat textile wastewater in a single reactor under intermittent anaerobic and aerobic conditions was developed in this study. The granules were cultivated using mixed sewage and textile mill sludge in combination with anaerobic granules collected from an anaerobic sludge blanket reactor as seed. The granules were developed in a single sequential batch reactor (SBR) system under alternating anaerobic and aerobic condition fed with synthetic textile wastewater. The characteristics of the microbial granular sludge were monitored throughout the study period. During this period, the average size of the granules increased from 0.02 ± 0.01 mm to 2.3 ± 1.0 mm and the average settling velocity increased from 9.9 ± 0.7 m h-1 to 80 ± 8 m h-1. This resulted in an increased biomass concentration (from 2.9 ± 0.8 g L-1 to 7.3 ± 0.9 g L-1) and mean cell residence time (from 1.4 days to 8.3 days). The strength of the granules, expressed as the integrity coefficient also improved. The sequential batch reactor system demonstrated good removal of COD and ammonia of 94% and 95%, respectively, at the end of the study. However, only 62% of color removal was observed. The findings of this study show that granular sludge could be developed in a single reactor with an intermittent anaerobic-aerobic reaction phase and is capable in treating the textile wastewater