Several models are available to model the effect of temperature on the growth rate of microorganism on substrates. One of the models is Arrhenius and is very popular due to it having few parameters. An apparent activation energy based on the Arrhenius plot on the growth on acrylamide by Pseudomonas sp. strain DRYJ7 on acrylamide is reported for the first time. The bacterium was grown in minimal salts media supplemented with 1000 mg/L of acrylamide as a nitrogen source and glucose as the carbon source. The plot of ln m (specific growth rate) against 1/T for growth on acrylamide was carried out spanning the range of temperature from 10 to 35 oC. Regression analysis from 10–20 oC results in an activation energy of 14.96 kJ mol-1. A relative 10 ˚C increase in the surrounding temperature, usually results in doubling the reaction rate, with corresponding Q10 value of 1.8, which is the approximate value for a number of biological reactions. The Q10 values, determined from the Arrhenius plot of 2.17 and a theta value of 1.03 obtained in this work, are within the normal range for many biological values. This is the first time that values for the activation energy, Q10 and theta for the growth of a bacterium on acrylamide is reported.

Widespread use of acrylamide by the industry led to the environmental pollution that results from the indiscriminate discharge of acrylamide. The presence of acrylamide in the environment is a major threat due to its neurotoxic, carcinogenic and teratogenic properties. In this work bacterial isolate identified as Burkholderia sp. strain AQ5-13 is capable of degrading acrylamide as both its carbon and nitrogen sources were screen based on the capability of the bacteria to grow on solid basal salt media that contain 500 mg/L acrylamide as sole carbon and nitrogen sources without supplementation of additional carbon or nitrogen sources. Bacteria grow curve study was carried out by measuring the absorbance value at 600 nm. Burkholderia sp. strain AQ5-13 showed a complete life cycle in five days of incubation with no lag phase identified at the earlier growth phase. Optimum conditions for acrylamide degradation was conducted at different initial pH and incubation temperature. Growth optimisation of the bacteria was measured by plate counting in CFU after 48 h of incubation in 250 mL basal salt media that contain 500 mg/L acrylamide. Burkholderia sp. strain AQ5-13 showed optimum growth in acidic media at pH 5.7 (5.57 log 10 CFU/mL) and optimum growth at 30°C (6.84 log 10 CFU/mL) compared to other temperature ranges. Quantitative monitoring of acrylamide degradation was performed using HPLC. Burkholderia sp. strain AQ5-13 could degrade 14% of 500 mg/L acrylamide as its carbon and nitrogen sources after 72 h of incubation at 5 min of retention time. The appearance of acrylic acid peak as an intermediate was not detected, possibly because all the acrylic acid produced had been consumed immediately by the bacterium. The result from this study showed that bacteria Burkholderia sp. strain AQ5-13 has a good potential that can be applied in the bioremediation of waste containing acrylamide.

Cholinesterase-based biosensor well known as a sensitive method to detect the existence of harmful dissolved compounds in any type of water source, especially the river. This alternative biosensor can be used to determine the level of pollution of the water in a short period of time as well as to evaluate the low cost and simple service. The aim of this study was to exceed the effectiveness of acetylcholinesterase source extracted from the brain tissue of Asian swamp eel; Monopterus albus as a potential environmental biosensor. Purified acetylcholinesterase exposed to a different type of metal ions and mercury showed the highest percentage of inhibition at 62.9% followed by chromium at 59.22% while silver, arsenic, cadmium, cobalt, copper, nickel, zinc a¬¬nd lead at not more than 50% (approximately 37-50%). Metal ions such as mercury, zinc, chromium and copper showed exponential decay type inhibition curves with calculated half maximal inhibitory concentration; IC50 in the ascending sensitivity order 0.005, 0.595, 0.687 and 1.329 mgL-1, respectively. Field trial works exhibited that the acetylcholinesterase was applicable in sensing heavy metals pollution from the river which closed to the industrial and agricultural sites at near real-time and verified using ICP-OES. This study proves the potential use of acetylcholinesterase sourced from M. albus as a biomonitoring tool to assess the contamination level of the river.

Contamination of organic xenobiotic pollutants and heavy metals in a contaminated site allows the use of multiple bacterial degraders or bacteria with the ability to detoxify numerous toxicants at the same time. A previously isolated SDS- degrading bacterium, Acinetobacter baumannii strain Serdang 1 was shown to reduce molybdenum to molybdenum-blue. The bacterium works optimally at pH 6.5, the temperature range between 25 and 34°C with glucose serves as the best electron donor for molybdate reduction. This bacterium required additional concentration of phosphate at 5.0 mM and molybdate between 15 and 25 mM. The absorption spectrum of the molybdenum blue obtained is similar to the molybdenum blue from other earlier reported molybdate reducing bacteria, as it resembles a reduced phosphomolybdate closely. Ag(i), As(v), Pb(ii) and Cu(ii) inhibited molybdenum reduction by 57.3, 36.8, 27.7 and 10.9%, respectively, at 1 p.p.m. Acrylamide was efficiently shown to support molybdenum reduction at a lower efficiency than glucose. Phenol, acrylamide and propionamide could support the growth of this bacterium independently of molybdenum reduction. This bacterium capability to detoxify several toxicants is an important tool for bioremediation in the tropical region

Synthetic dyes are abundantly used in recent years and mainly consumed in the textile, pharmaceutical, plastic and cosmetic industries. The release of toxic constituents from dyes give adverse effect on human health and marine life. In textile industries, large amount of dye discharged into the wastewater and eventually to the aquatic system are mainly came from the critical step of dyeing and finishing processes in textile. The be able to precisely forecast the rate of bioremediation, depends on the gathering of precise rate of decolourisation, and this can be inaccurately acquired by natural logarithm transformation of the decolourisation process over time. In cases like this, a nonlinear regression of the curve must be performed making use of accessible rate models. Consequently, numerous primary models for example modified Logistic, modified Gompertz, modified logistics, modified Richards, modified Schnute, Baranyi-Roberts, Buchanan-3-phase, von Bertalanffy and the Huang models were utilized to fit the specific decolourisation rate. Several models did not converge and was disregarded and only Huang, Baranyi-Roberts, modified Gompertz, modified Richards and modified Logistics could actually model the data. The very best model according to statistical analysis was Baranyi Roberts with the highest value for Adjusted Coefficient of Determination and the lowest values for RMSE, AICc, HQC and BIC and the closest value to 1.0 for accuracy and bias factors. The Baranyi-Roberts fitted curve was discovered to conform to normality tests and is satisfactory to be used to fit the experimental data. The parameters extracted from this exercise may be used for additional secondary modelling training to gleam information about how substrate (dye) impact the rate of decolourisation of the substrate