A major source of acrylamide in soil comes from herbicide formulation that contained polyacrylamide that slowly decomposes to acrylamide. Research in acrylamide biodegradation by microbe as a tool for its bioremediation is slowly gaining attention globally. In this research, a hydrocarbon-degrading Pseudomonas sp. strain Dr Y Kertih isolated from petroleum sludge was able to grow on acrylamide. The results show that 1% (w/v) glucose supplied with acrylamide (as the only nitrogen source) was the best carbon source for the growth of acrylamide-degrading bacterium. The isolate was also able to use diesel as a carbon source. The bacterium shows an optimal growth at 300 mg/L acrylamide, pH between pH 6.5 and 7.5 and temperature between 25 and 30 °C. The isolate was able to grow on amides such as acetamide and 2-chloroacetamide, but their growth was inhibited by toxic heavy metals such as mercury, cadmium and chromium. Growth kinetic studies using the Haldane model for growth indicated substrate toxicity at higher concentrations on acrylamide. The maximum growth rate (µmax) was 0.267 h-1 while the saturation constant or half velocity constant Ks and inhibition constant Ki, were 0.182 and 0.25 g/L, respectively. Thus, the bacterium holds great potential as a candidate to remediate acrylamide.

Due to the increase in pesticide usage the cost of food production has been drastically reduced worldwide. There are dangers related to the ever-increasing pesticide application especially to the non-target biota and to also to the environment at large. Pesticides bind with the active site of acetylcholinesterase (AChE) and inhibit the breakdown of acetylcholine and causes the blockage of synaptic transmission in cholinergic nerves. When AChE is inhibited, ChE accumulates and the nerve impulse cannot be stopped, leading to muscle contraction, paralysis and sometimes dead may occur. Pesticides and other chemicals that inhibit AChE activity can be able to cause abnormal behavioural patterns of the affected animals. The effects of AChE inhibition in vertebrate include vasodilation of blood vessels, slower heart rate, constriction of bronchioles and reduced secretion of mucus in the respiratory tract, intestinal cramps, secretion of saliva, sweat and tears, and constriction of eye pupil. The inhibition of the AChE activity will also definitely affect the optomotor behaviour of a fish which in turn will affect feeding capability, identification and avoidance of predators, and spatial orientation of the species. Carbamates, organophosphate and eserine are the major pesticides that inhibit the AChE activity of many animals. Cholinesterases including AChE have been considered as interesting biomarkers and biosensor for many years in the monitoring of environmental contamination. This is sensitive to selected organophosphate and carbamate pesticides and may be responding to low levels of contaminants in the environment, putatively by compounds other than or in addition to pesticides. In respect to the above AChE is regarded as a good Biosensor and biomarker in assessing pesticides and other chemical pollutants in the environment.

The Q10 value is tied to an increase in the surrounding temperature with an increase in 10 â—¦C, and usually resulted in a doubling of the reaction rate. When this happens, the Q10 value for the reaction is 2. This value holds true to numerous biological reactions. To date, the Q10 value for the biodegradation of phenol is almost not reported. The Q10 values can be determined from the Arrhenius plots. In this study, the growth rate or biodegradation rates in logarithmic value for the bacterium Pseudomonas sp. AQ5-04 was plotted against 1000/temperature (Kelvin) and the slope of the Arrhenius curve is the value of the Ea, which was utilized to obtain the Q10. The value obtained in this work was 1.834, which is slightly lower than the normal range of between 2 and 3 for the biodegradation rates of hydrocarbon in general and shows that this bacterium is a very efficient phenol-degrading bacterium.

Phenol is mainly used by the industries to produce a variety of chemical products such as resins, textiles, pesticides, plastics and explosive. The wide use of phenol and other phenolic compounds by industries, has resulted in an increased presence of these toxic compounds in the environment as pollutants. Bio-removal of phenol by microorganisms especially bacteria has been demonstrated to be the most effective and economical approach compared to physio-chemical methods. The search for efficient phenol-degraders especially local sources to remediate local phenol pollution is important as indigenous bacteria usually have better survival and resilient to local geographical conditions. In this study, a phenol-degrading microorganism was isolated from local soil and waste water bodies. Identification was carried out using gram staining, 16s rRNA gene sequencing and molecular phylogeny analysis using the Phylip software. The isolates were inoculated in mineral salt media with 0.5 g/L phenol as the sole source of carbon. Phenol degradation was determined using 4-amino antipyrine method. Physical and cultural conditions influencing phenol degradation such as pH and temperature were optimized via one-factor-at-a-time. Through phylogeny analysis, the isolate was identified as Serratia sp. and the sequence was deposited the NCBI Genebank and accession number KT693287 was assigned to the bacteria. The highest degradation was achieved at pH 7.5 (phosphate buffer) and temperature of 30°C. Ammonium sulphate was established to be the best nitrogen source at the concentration of 0.4 g/L and a sodium chloride concentration of 0.15 g/L. Aisami, A. | Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, Selangor, Malaysia

Phenol is widely used by many industries and it is one of the highly toxic environmental pollutants. Bioremoval is one of the most effective methods to remove phenol compared to other physio-chemical methods. Identification was carried out using 16s rRNA sequencing. Mineral salt media with 0.5 g/L phenol as the sole source of carbon. Factors influencing phenol degradation were optimised via onefactor-at-a-time and response surface methodology. Optimum degradation was achieved at pH 7.5, the temperature of 30°C and ammonium sulphate at 0.4 g/L. Using Response surface methodology the incubation period was reduced to 36 h compared to the OFAT approach where it takes 72 hours. The effect of 10 heavy metals at various concentrations was tested. The optimum values used for temperature, pH, ammonium sulphate and salinity for both the OFAT and RSM have correlated with the only pH displayed the slighted difference of 7.0 for OFAT and 7.5 for RSM. This shows the closest optimum conditions for both methods. The strain is also resistance to some heavy metals usually found in polluted environments together with phenol. Therefore, it can be clearly stated that Pseudomonas sp. strain AQ5-04 is the potential candidate for phenol bioremediation and further studies in the field of bioremediation. The bacterium can degrade phenol in the presence of between 1 to 3 ppm of the heavy metals As, Cd, Co, and Zn while growth and degradation were inhibited by Hg, Ag, Cu and Ni at 1 ppm. The isolate is a potential strain for further bioremediation studies.