The Malacca river runs through the Malacca UNESCO heritage site where a number of historical buildings are located. The river itself runs through several industrial sites that increase the chances of the water being polluted. Water pollution including heavy metals, in the long run, can damage the reputation of the site. Hence monitoring of the water quality needs to be done periodically. As the cost of instrumental monitoring is costly, biomonitoring using enzyme is being intensely developed worldwide. In this study, a rapid inhibitive enzyme assay using the molybdenum-reducing enzyme from the bacterium Serratia sp. strain DRY6 sensitive to the heavy metals mercury, copper, silver, and chromium was developed as a method for a rapid monitoring of heavy metals. The IC¬50 values for mercury, copper, silver and chromium were 0.268, 0.352, 0.393 and 0.499 mg L-1, while the LOD values were 0.166, 0.071, 0.033 and 0.064 mg L-1, respectively. The IC50 values for these heavy metals are comparable and in several cases, more sensitive than established assays. Water samples from various locations in the Melaka river were tested for the presence of heavy metals using the developed assay. Enzyme activity was found to be inhibited in one sampling location, but the concentration of metal ions on the site was found to be below the Maximum Permissible Limit according to Malaysian Environmental Quality standard. The assay for heavy metals can be completed in less than 10 minutes and can be carried out at ambient temperature. The assay is rapid and simple and can be used as a first screening method or even near real-time method for routine monitoring of heavy metals.
Glyphosate is an agricultural herbicide with usage in the amounts of thousands of tonnes per year
in Malaysia. In certain soils, glyphosate can persist for months and its removal through
bioremediation is the most economical and practical. A previously isolated glyphosate-degrading
bacterium showed substrate inhibition to the degradation rate. Important degradation inhibition
constants can be reliably obtained through nonlinear regression modelling of the degradation rate
profile using substrate inhibition models such as Luong, Yano, Teissier-Edward, Aiba, Haldane,
Monod and Han and Levenspiel models. The Aiba model was chosen as the best model based on
statistical tests such as root-mean-square error (RMSE), adjusted coefficient of determination
(adjR2), bias factor (BF) and accuracy factor (AF). The calculated values for the Aiba-Edwards
constants qmax (the maximum specific substrate degradation rate (h−1), Ks (concentration of
substrate at the half maximal degradation rate (mg/L) and Ki (inhibition constant (mg/L)) were
131±34, 4446±2073, and 24323±5094, respectively. Novel constants obtained from the
modelling exercise would be useful for further secondary modelling implicating the effect of
media conditions and other factors on the degradation of glyphosate by this bacterium.
Feather waste is a potential renewable source to recover valuable products because it is being a rich source of keratin proteins and amino acids. It can be used to make feather meal, fertilizer and yarn sizing agent. Various treatments have been used to recover the protein from chicken feathers as the keratinous feathers cannot be easily degraded due to its tough structure. This paper reviews the existing treatment methods used to hydrolyze chicken feathers. The treatment methods for feather hydrolysis such as physical, chemical, biological and combined treatments as well as their advantages and challenges are highlighted. The effects of these treatments on feather hydrolysis are complex and vary in regards to the performance of feather hydrolysis and product yielded. Hence, it is important to choose an appropriate treatment method since the type of treatment applied affects the product yielded qualitatively and quantitatively. In addition, the economic assessment and environmental impact of the choice of treatment should be considered also.
Commercialisation of glyphosate [N-(phosphonomethyl)glycine] in the early 1970s has left a big leap in the agriculture sector. This is due to its effectiveness in controlling a wide range of weeds. Glyphosate translocates well in plants. In addition, with added surfactant in its formulae, it can also be used in wet conditions. Its ability to kill weeds by targeting the 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) makes no competing herbicide analogs in its class. Considering its cost effectiveness, only small amount is needed to cover a large sector in agricultural land. The most important aspect in the success of glyphosate is the introduction of transgenic, glyphosate-resistant crops in 1996. However, glyphosate is not an environmental friendly herbicide. This systematic herbicide has raised environmental concern due to its excessive use in agriculture. Studies have shown traces of glyphosate found in drinking water. Meanwhile, it's rapid binding on soil particles possesses adverse effect to soil organisms. Glyphosate degradation in soil usually carried out by microbial activity. Microbes’ capable utilising glyphosate mainly as phosphate source. However, the activity of C-P lyase in breaking down glyphosate have not clearly understood. This review presents a collective summary on the understanding on how glyphosate works and its environmental fate.
The increase of anthropogenic activities and growth of technology in Antarctica is fuelled by the high demand for petroleum hydrocarbons needed for daily activities. Oil and fuel spills that occur during explorations have caused hydrocarbon pollution in this region, prompting concern for the environment by polar communities and the larger world community. Crude oil and petroleum hydrocarbon products contain a wide variety of lethal components with high toxicity and low biodegradability. Hydrocarbon persistence in the Antarctic environment only worsens the issues stemming from environmental pollution as they can be long-term. Numerous efforts to lower the contamination level caused by these pollutants have been conducted mainly in bioremediation, an economical and degrading-wise method. Bioremediation mainly functions on conversion of complex toxic compounds to simpler organic compounds due to the consumption of hydrocarbons by microorganisms as their energy source. This review presents a summary of the collective understanding on bioremediation of petroleum hydrocarbons by microorganisms indigenous to the Antarctic region from past decades to current knowledge.
This study reports on the characterization of a purified AChE from Oreochromis mossambica
brain extract. The purification protocol involved the application of custom-synthesized affinity
chromatography gel (Edrophonium–Sephacryl S-400) and the use of high performance liquid
chromatography system (HPLC). Soluble AChE was partially purified 27.9 fold with a highest
specific activity around 73.1 × 103 U/mg proteins. The partially purified AChE higher capability
to hydrolyse acetylthiocholine (ATC) and shows less degradation against propionylthiocholine
(PTC) and also butyrylthiocholine (BTC). Based on enzyme kinetic analysis, the partially
purified AChE exhibits the apparent Michaelis constants Km, for ATC, PTC and BTC in the
range of 125, 260 and 600 μM and the maximum velocities Vmax were 276, 59 and 36
μmol/min/mg protein, respectively. The apparent inhibition constant (ki) values of eserine,
propidium and carbofuran were 0.24 μM-1min-1, 65 μM-1min-1 and 0.41 μM-1min-1 μM-1min-1,
respectively. The purified enzyme is apparently an AChE since it capable to hydrolyzes ATC at a
higher rate compared to other synthetic substrates, at pH 7.0 and 25ºC, and is inhibited by it
specific inhibitor which is eserine but not by iso-OMPA.
Despite wide applications in industries, phenol pollution leads to many health effects, and one of the technologies used to clean up phenol pollution is phytoremediation. The aim of this research was to assess the remediation ability of Ipomoea aquatica Forssk., which is easy to handle and and has a fast growth rate. Plantlet was grown in water spiked with 0.05, 0.10, 0.20, 0.30 and 0.40 g/L phenol, followed by daily observation of the plantlets morphology and tracking of phenol concentration in the water and plantlet extracts via 4-aminoantipyrine (4-AAP) assay. Plantlet’s roots in 0.10 g/L phenol (57.42 ± 1.41 mm) were significantly longer (p < 0.05) than those of the control plantlets (43.57 ± 3.87 mm) in contrast to other phenol concentrations which had stunted roots growth. I. aquatica Forssk. was able to survive with 0.30 g/L phenol despite exhibiting yellowing of leaves and increased sensitivity to scarring on the stems. The plantlets were able to completely remove the phenol from the water spiked with phenol at 0.05 g/L after 12 days of growth. However, the highest average rate of phenol removal was 0.021 g/L/day from water spiked with 0.30 g/L phenol. Phenol analysis on the plantlets’ extracts revealed that I. aquatica Forssk. had degraded the absorbed phenol. This observation is of significant interest as it highlights the
potential of I. aquatica Forssk. for use as a phytoremediator to clean up phenol contaminated water.
Recently, the contamination of heavy metals towards the environment especially in aquatic system has drastically increased. Heavy metals are able to transform into persistent metallic compound in which it can be accumulated within the organisms’ body system, disrupting the food chain and eventually threatened the human life. The occurrence of heavy metals spillage in the rivers and lakes are due to the careless disposal of excess heavy metals used for human activities. The accumulation of heavy metals in water system will affect all aquatic organisms especially fish. The toxicity of copper in fish can be determined by several changes in the fish under treatment with heavy metals sub-lethal concentration, LC50 within 96-hours period of acute exposure. Therefore, fish can be considered as a high potential biomarker for monitoring heavy metals pollution in aquatic system. Several selective organs are highly sensitive to the xenobiotic pollution and express changes to the exposure. One of the most potential biomarker is the biochemical biomarker of cholinesterase (ChE) inhibition by heavy metals in fish has been well studied in pollution monitoring recently. Thus, this paper gives an overview of the manipulation of fish as a biomarker of heavy metals through enzymatic reaction which have proven to be very useful in the environmental pollution monitoring.