Displaying publications 1 - 20 of 37 in total

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  1. Two-stage bile preparation with acetone for recovery of fluorescent aromatic compounds (FACs)
    Karami A, Syed MA, Christianus A, Willett KL, Mazzeo JR, Courtenay SC
    J Hazard Mater, 2012 Jul 15;223-224:84-93.
    PMID: 22608400 DOI: 10.1016/j.jhazmat.2012.04.051
    In this study we sought to optimize recovery of fluorescent aromatic compounds (FACs) from the bile of African catfish (Clarias gariepinus) injected with 10mg/kg benzo[a]pyrene (BaP). Fractions of pooled bile were hydrolyzed, combined with ten volumes of methanol, ethanol, acetonitrile, or acetone, centrifuged and supernatants were analyzed by high-performance liquid chromatography with fluorescent detection (HPLC/FL). As well, to test whether FACs were being lost in solids from the centrifugation, pellets were resuspended, hydrolyzed and mixed with six volumes of the organic solvent that produced best FAC recovery from the supernatant, and subjected to HPLC/FL. Highest FAC concentrations were obtained with 2000μl and 1250μl acetone for supernatants and resuspended pellets respectively. FACs concentrations were negatively correlated with biliary protein content but were unaffected by addition of bovine serum albumin (BSA) followed by no incubation indicating that the presence of proteins in the biliary mixture does not simply interfere with detection of FACs. In another experiment, efficiency of acetone addition was compared to two different liquid-liquid extractions (L-LEs). Acetone additions provided significantly higher biliary FACs than the L-LE methods. The new two-stage bile preparation with acetone is an efficient, inexpensive and easily performed method.
  2. The effects of intramuscular and intraperitoneal injections of benzo[a]pyrene on selected biomarkers in Clarias gariepinus
    Karami A, Christianus A, Ishak Z, Syed MA, Courtenay SC
    Ecotoxicol Environ Saf, 2011 Sep;74(6):1558-66.
    PMID: 21636131 DOI: 10.1016/j.ecoenv.2011.05.012
    This study investigated the dose-dependent and time-course effects of intramuscular (i.m.) and intraperitoneal (i.p.) injection of benzo[a]pyrene (BaP) on the biomarkers EROD activity, GST activity, concentrations of BaP metabolites in bile, and visceral fat deposits (Lipid Somatic Index, LSI) in African catfish (Clarias gariepinus). Intraperitoneal injection resulted in 4.5 times higher accumulation of total selected biliary FACs than i.m. injection. Hepatic GST activities were inhibited by BaP via both injection methods. Dose-response relationships between BaP injection and both biliary FAC concentrations and hepatic GST activities were linear in the i.p. injected group but nonlinear in the i.m. injected fish. Hepatic EROD activity and LSI were not significantly affected by BaP exposure by either injection route. We conclude that i.p. is a more effective route of exposure than i.m. for future ecotoxicological studies of PAH exposure in C. gariepinus.
  3. The development of an inhibitive determination method for zinc using a serine protease
    Shukor MY, Baharom NA, Masdor NA, Abdullah MP, Shamaan NA, Jamal JA, et al.
    J Environ Biol, 2009 Jan;30(1):17-22.
    PMID: 20112858
    A new inhibitive heavy metals determination method using trypsin has been developed. The enzyme was assayed using the casein-Coomassie-dye-binding method. In the absence of inhibitors, casein was hydrolysed to completion and the Coomassie-dye was unable to stain the protein and the solution became brown. In the presence of metals, the hydrolysis of casein was inhibited and the solution remained blue. The bioassay was able to detect zinc and mercury with IC50 (concentration causing 50% inhibition) values of 5.78 and 16.38 mg l(-1) respectively. The limits of detection (LOD), for zinc and mercury were 0.06 mg l(-1) (0.05-0.07, 95% confidence interval) and 1.06 mg l(-1) (1.017-1.102, 95% confidence interval), respectively. The limits of quantitation (LOQ) for zinc and mercury were 0.61 mg l(-1) (0.51-0.74 at a 95% confidence interval) and 1.35 mg l(-1) (1.29-1.40 at a 95% confidence interval), respectively. The IC50 value for zinc was much higher than the IC50 values for papain and Rainbow trout, but was within the range of Daphnia magna and Microtox. The IC50 value for zinc was only lower than those for immobilized urease. Other toxic heavy metals, such as lead, silver arsenic, copper and cadmium, did not inhibit the enzyme at 20 mg l(-1). Using this assay we managed to detect elevated zinc concentrations in several environmental samples. Pesticides, such as carbaryl, flucythrinate, metolachlor glyphosate, diuron, diazinon, endosulfan sulphate, atrazine, coumaphos, imidacloprid, dicamba and paraquat, showed no effect on the activity of trypsin relative to control (One-way ANOVA, F(12,26)= 0.3527, p> 0.05). Of the 17 xenobiotics tested, only (sodium dodecyl sulphate) SDS gave positive interference with 150% activity higher than that of the control at 0.25% (v/v).
  4. Fulltext The assessment of cholinesterase from the liver of Puntius javanicus as detection of metal ions
    Sabullah MK, Sulaiman MR, Abd Shukor MY, Syed MA, Shamaan NA, Khalid A, et al.
    ScientificWorldJournal, 2014;2014:571094.
    PMID: 25401148 DOI: 10.1155/2014/571094
    Crude extract of ChE from the liver of Puntius javanicus was purified using procainamide-sepharyl 6B. S-Butyrylthiocholine iodide (BTC) was selected as the specific synthetic substrate for this assay with the highest maximal velocity and lowest biomolecular constant at 53.49 µmole/min/mg and 0.23 mM, respectively, with catalytic efficiency ratio of 0.23. The optimum parameter was obtained at pH 7.5 and optimal temperature in the range of 25 to 30°C. The effect of different storage condition was assessed where ChE activity was significantly decreased after 9 days of storage at room temperature. However, ChE activity showed no significant difference when stored at 4.0, 0, and -25°C for 15 days. Screening of heavy metals shows that chromium, copper, and mercury strongly inhibited P. javanicus ChE by lowering the activity below 50%, while several pairwise combination of metal ions exhibited synergistic inhibiting effects on the enzyme which is greater than single exposure especially chromium, copper, and mercury. The results showed that P. javanicus ChE has the potential to be used as a biosensor for the detection of metal ions.
  5. Reduction of molybdate to molybdenum blue by Klebsiella sp. strain hkeem
    Lim HK, Syed MA, Shukor MY
    J Basic Microbiol, 2012 Jun;52(3):296-305.
    PMID: 22052341 DOI: 10.1002/jobm.201100121
    A novel molybdate-reducing bacterium, tentatively identified as Klebsiella sp. strain hkeem and based on partial 16s rDNA gene sequencing and phylogenetic analysis, has been isolated. Strain hkeem produced 3 times more molybdenum blue than Serratia sp. strain Dr.Y8; the most potent Mo-reducing bacterium isolated to date. Molybdate was optimally reduced to molybdenum blue using 4.5 mM phosphate, 80 mM molybdate and using 1% (w/v) fructose as a carbon source. Molybdate reduction was optimum at 30 °C and at pH 7.3. The molybdenum blue produced from cellular reduction exhibited absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Inhibitors of electron transport system such as antimycin A, rotenone, sodium azide, and potassium cyanide did not inhibit the molybdenum-reducing enzyme. Mercury, silver, and copper at 1 ppm inhibited molybdenum blue formation in whole cells of strain hkeem.
  6. Reduction of molybdate to molybdenum blue by Enterobacter sp. strain Dr.Y13
    Shukor MY, Rahman MF, Shamaan NA, Syed MA
    J Basic Microbiol, 2009 Sep;49 Suppl 1:S43-54.
    PMID: 19455513 DOI: 10.1002/jobm.200800312
    Extensive use of metals in various industrial applications has caused substantial environmental pollution. Molybdenum-reducing bacteria isolated from soils can be used to remove molybdenum from contaminated environments. In this work we have isolated a local bacterium with the capability to reduce soluble molybdate to the insoluble molybdenum blue. We studied several factors that would optimize molybdate reduction. Electron donor sources such as glucose, sucrose, lactose, maltose and fructose (in decreasing efficiency) supported molybdate reduction after 24 h of incubation with optimum glucose concentration for molybdate reduction at 1.5% (w/v). The optimum pH, phosphate and molybdate concentrations, and temperature for molybdate reduction were pH 6.5, 5.0, 25 to 50 mM and 37 degrees C, respectively. The Mo-blue produced by cellular reduction exhibited a unique absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Metal ions such as chromium, cadmium, copper, silver and mercury caused approximately 73, 71, 81, 77 and 78% inhibition of the molybdenum-reducing activity, respectively. All of the respiratory inhibitors tested namely rotenone, azide, cyanide and antimycin A did not show any inhibition to the molybdenum-reducing activity suggesting components of the electron transport system are not responsible for the reducing activity. The isolate was tentatively identified as Enterobacter sp. strain Dr.Y13 based on carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny.
  7. Reduction of Mo(VI) by the bacterium Serratia sp. strain DRY5
    Rahman MF, Shukor MY, Suhaili Z, Mustafa S, Shamaan NA, Syed MA
    J Environ Biol, 2009 Jan;30(1):65-72.
    PMID: 20112865
    The need to isolate efficient heavy metal reducers for cost effective bioremediation strategy have resulted in the isolation of a potent molybdenum-reducing bacterium. The isolate was tentatively identified as Serratia sp. strain DRY5 based on the Biolog GN carbon utilization profiles and partial 16S rDNA molecular phylogeny. Strain DRY5 produced 2.3 times the amount of Mo-blue than S. marcescens strain Dr.Y6, 23 times more than E. coli K12 and 7 times more than E. cloacae strain 48. Strain DRY5 required 37 degrees C and pH 7.0 for optimum molybdenum reduction. Carbon sources such as sucrose, maltose, glucose and glycerol, supported cellular growth and molybdate reduction after 24 hr of static incubation. The most optimum carbon source that supported reduction was sucrose at 1.0% (w/v). Ammonium sulphate, ammonium chloride, glutamic acid, cysteine, and valine supported growth and molybdate reduction with ammonium sulphate as the optimum nitrogen source at 0. 2% (w/v). Molybdate reduction was optimally supported by 30 mM molybdate. The optimum concentration of phosphate for molybdate reduction was 5 mM when molybdate concentration was fixed at 30 mM and molybdate reduction was totally inhibited at 100 mM phosphate. Mo-blue produced by this strain shows a unique characteristic absorption profile with a maximum peak at 865 nm and a shoulder at 700 nm, Dialysis tubing experiment showed that 95.42% of Mo-blue was found in the dialysis tubing suggesting that the molybdate reduction seen in this bacterium was catalyzed by enzyme(s). The characteristics of isolate DRY5 suggest that it would be useful in the bioremediation ofmolybdenum-containing waste.
  8. Quality of life in Malaysian colorectal cancer patients: a preliminary result
    Natrah MS, Ezat S, Syed MA, Rizal AM, Saperi S
    Asian Pac J Cancer Prev, 2012;13(3):957-62.
    PMID: 22631679
    OBJECTIVE: Rapidly increasing colorectal cancer (CRC) incidence in Malaysia and the introduction of cutting edge new treatments, which prolong survival, mean that treatment outcome measures meed to be evaluated, including consideration of patient's quality of life (QoL) assessment. There are limited data on QoL in CRC patients, especially in Malaysia. Therefore, this study was performed focusing on cancer stages and age groups.

    METHODS: The cross sectional study was conducted from June to September 2011 at three public tertiary hospitals with the EORTC QLQ C-30 questionnaire in addition to face to face interview and review of medical records of 100 respondents.

    RESULTS: The mean age was 57.3 (SD 11.9) years with 56.0% are males and 44.0% females, 62% of Malay ethnicity, 30% Chinese, 7% Indian and 1% Sikh. Majority were educated up to secondary level (42%) and 90% respondents had CRC stages III and IV. Mean global health status (GHS) score was 79.1 (SD 21.4). Mean scores for functional status (physical, emotional, role, cognitive, social) rangeds between 79.5 (SD 26.6) to 92.2 (SD 13.7). Mean symptom scores (fatigue, pain, nausea/vomiting, constipation, diarrhea, insomnia, dyspnoea, loss of appetite) ranged between 4.00 (SD 8.58) to 20.7 (SD 30.6). Respondents role function significantly deteriorates with increasing stage of the disease (p=0.044). Females had worse symptoms of pain (p=0.022), fatigue (p=0.031) and dyspnoea (p=0.031). Mean insomnia (p=0.006) and diarrhea (p=0.024) demonstrated significant differences between age groups.

    CONCLUSION: QOL in CRC patients in this study was comparable to that in other studies done in developed countries. Pain, fatigue and dyspnoea are worse among female CRC patients. Given that functions deteriorates with advanced stage of the disease at diagnosis, a systematic screening programme to detect cases as early as possible is essential nationwide.

  9. Fulltext Molybdenum reduction to molybdenum blue in Serratia sp. Strain DRY5 is catalyzed by a novel molybdenum-reducing enzyme
    Shukor MY, Halmi MI, Rahman MF, Shamaan NA, Syed MA
    Biomed Res Int, 2014;2014:853084.
    PMID: 24724104 DOI: 10.1155/2014/853084
    The first purification of the Mo-reducing enzyme from Serratia sp. strain DRY5 that is responsible for molybdenum reduction to molybdenum blue in the bacterium is reported. The monomeric enzyme has an apparent molecular weight of 105 kDalton. The isoelectric point of this enzyme was 7.55. The enzyme has an optimum pH of 6.0 and maximum activity between 25 and 35°C. The Mo-reducing enzyme was extremely sensitive to temperatures above 50°C (between 54 and 70°C). A plot of initial rates against substrate concentrations at 15 mM 12-MP registered a V max for NADH at 12.0 nmole Mo blue/min/mg protein. The apparent K m for NADH was 0.79 mM. At 5 mM NADH, the apparent V max and apparent K m values for 12-MP of 12.05 nmole/min/mg protein and 3.87 mM, respectively, were obtained. The catalytic efficiency (k cat/K m ) of the Mo-reducing enzyme was 5.47 M(-1) s(-1). The purification of this enzyme could probably help to solve the phenomenon of molybdenum reduction to molybdenum blue first reported in 1896 and would be useful for the understanding of the underlying mechanism in molybdenum bioremediation involving bioreduction.
  10. Fulltext Molybdate reduction to molybdenum blue by an Antarctic bacterium
    Ahmad SA, Shukor MY, Shamaan NA, Mac Cormack WP, Syed MA
    Biomed Res Int, 2013;2013:871941.
    PMID: 24381945 DOI: 10.1155/2013/871941
    A molybdenum-reducing bacterium from Antarctica has been isolated. The bacterium converts sodium molybdate or Mo⁶⁺ to molybdenum blue (Mo-blue). Electron donors such as glucose, sucrose, fructose, and lactose supported molybdate reduction. Ammonium sulphate was the best nitrogen source for molybdate reduction. Optimal conditions for molybdate reduction were between 30 and 50 mM molybdate, between 15 and 20°C, and initial pH between 6.5 and 7.5. The Mo-blue produced had a unique absorption spectrum with a peak maximum at 865 nm and a shoulder at 710 nm. Respiratory inhibitors such as antimycin A, sodium azide, potassium cyanide, and rotenone failed to inhibit the reducing activity. The Mo-reducing enzyme was partially purified using ion exchange and gel filtration chromatography. The partially purified enzyme showed optimal pH and temperature for activity at 6.0 and 20°C, respectively. Metal ions such as cadmium, chromium, copper, silver, lead, and mercury caused more than 95% inhibition of the molybdenum-reducing activity at 0.1 mM. The isolate was tentatively identified as Pseudomonas sp. strain DRY1 based on partial 16s rDNA molecular phylogenetic assessment and the Biolog microbial identification system. The characteristics of this strain would make it very useful in bioremediation works in the polar and temperate countries.
  11. Fulltext Molybdate reduction by Pseudomonas sp. strain DRY2
    Shukor MY, Ahmad SA, Nadzir MM, Abdullah MP, Shamaan NA, Syed MA
    J Appl Microbiol, 2010 Jun;108(6):2050-8.
    PMID: 19968732 DOI: 10.1111/j.1365-2672.2009.04604.x
    To isolate and characterize a potent molybdenum-reducing bacterium.
  12. Fulltext Microbiological Reduction of Molybdenum to Molybdenum Blue as a Sustainable Remediation Tool for Molybdenum: A Comprehensive Review
    Yakasai HM, Rahman MF, Manogaran M, Yasid NA, Syed MA, Shamaan NA, et al.
    Int J Environ Res Public Health, 2021 May 27;18(11).
    PMID: 34071757 DOI: 10.3390/ijerph18115731
    Molybdenum (Mo) microbial bioreduction is a phenomenon that is beginning to be recognized globally as a tool for the remediation of molybdenum toxicity. Molybdenum toxicity continues to be demonstrated in many animal models of spermatogenesis and oogenesis, particularly those of ruminants. The phenomenon has been reported for more than 100 years without a clear understanding of the reduction mechanism, indicating a clear gap in the scientific knowledge. This knowledge is not just fundamentally important-it is specifically important in applications for bioremediation measures and the sustainable recovery of metal from industrial or mine effluent. To date, about 52 molybdenum-reducing bacteria have been isolated globally. An increasing number of reports have also been published regarding the assimilation of other xenobiotics. This phenomenon is likely to be observed in current and future events in which the remediation of xenobiotics requires microorganisms capable of degrading or transforming multi-xenobiotics. This review aimed to comprehensively catalogue all of the characterizations of molybdenum-reducing microorganisms to date and identify future opportunities and improvements.
  13. Fulltext Kinetics of molybdenum reduction to molybdenum blue by Bacillus sp. strain A.rzi
    Othman AR, Bakar NA, Halmi MI, Johari WL, Ahmad SA, Jirangon H, et al.
    Biomed Res Int, 2013;2013:371058.
    PMID: 24369531 DOI: 10.1155/2013/371058
    Molybdenum is very toxic to agricultural animals. Mo-reducing bacterium can be used to immobilize soluble molybdenum to insoluble forms, reducing its toxicity in the process. In this work the isolation of a novel molybdate-reducing Gram positive bacterium tentatively identified as Bacillus sp. strain A.rzi from a metal-contaminated soil is reported. The cellular reduction of molybdate to molybdenum blue occurred optimally at 4 mM phosphate, using 1% (w/v) glucose, 50 mM molybdate, between 28 and 30 °C and at pH 7.3. The spectrum of the Mo-blue product showed a maximum peak at 865 nm and a shoulder at 700 nm. Inhibitors of bacterial electron transport system (ETS) such as rotenone, sodium azide, antimycin A, and potassium cyanide could not inhibit the molybdenum-reducing activity. At 0.1 mM, mercury, copper, cadmium, arsenic, lead, chromium, cobalt, and zinc showed strong inhibition on molybdate reduction by crude enzyme. The best model that fitted the experimental data well was Luong followed by Haldane and Monod. The calculated value for Luong's constants p max, K(s), S(m), and n was 5.88 μmole Mo-blue hr(-1), 70.36 mM, 108.22 mM, and 0.74, respectively. The characteristics of this bacterium make it an ideal tool for bioremediation of molybdenum pollution.
  14. Keratinase production and biodegradation of polluted secondary chicken feather wastes by a newly isolated multi heavy metal tolerant bacterium-Alcaligenes sp. AQ05-001
    Yusuf I, Ahmad SA, Phang LY, Syed MA, Shamaan NA, Abdul Khalil K, et al.
    J Environ Manage, 2016 Dec 01;183:182-95.
    PMID: 27591845 DOI: 10.1016/j.jenvman.2016.08.059
    Biodegradation of agricultural wastes, generated annually from poultry farms and slaughterhouses, can solve the pollution problem and at the same time yield valuable degradation products. But these wastes also constitute environmental nuisance, especially in Malaysia where their illegal disposal on heavy metal contaminated soils poses a serious biodegradation issue as feather tends to accumulate heavy metals from the surrounding environment. Further, continuous use of feather wastes as cheap biosorbent material for the removal of heavy metals from effluents has contributed to the rising amount of polluted feathers, which has necessitated the search for heavy metal-tolerant feather degrading strains. Isolation, characterization and application of a novel heavy metal-tolerant feather-degrading bacterium, identified by 16S RNA sequencing as Alcaligenes sp. AQ05-001 in degradation of heavy metal polluted recalcitrant agricultural wastes, have been reported. Physico-cultural conditions influencing its activities were studied using one-factor-at-a-time and a statistical optimisation approach. Complete degradation of 5 g/L feather was achieved with pH 8, 2% inoculum at 27 °C and incubation period of 36 h. The medium optimisation after the response surface methodology (RSM) resulted in a 10-fold increase in keratinase production (88.4 U/mL) over the initial 8.85 U/mL when supplemented with 0.5% (w/v) sucrose, 0.15% (w/v) ammonium bicarbonate, 0.3% (w/v) skim milk, and 0.01% (w/v) urea. Under optimum conditions, the bacterium was able to degrade heavy metal polluted feathers completely and produced valuable keratinase and protein-rich hydrolysates. About 83% of the feathers polluted with a mixture of highly toxic metals were degraded with high keratinase activities. The heavy metal tolerance ability of this bacterium can be harnessed not only in keratinase production but also in the bioremediation of heavy metal-polluted feather wastes.
  15. Isolation and characterization of an acrylamide-degrading yeast Rhodotorula sp. strain MBH23 KCTC 11960BP
    Rahim MB, Syed MA, Shukor MY
    J Basic Microbiol, 2012 Oct;52(5):573-81.
    PMID: 22144174 DOI: 10.1002/jobm.201100116
    As well as for chemical and environmental reasons, acrylamide is widely used in many industrial applications. Due to its carcinogenicity and toxicity, its discharge into the environment causes adverse effects on humans and ecology alike. In this study, a novel acrylamide-degrading yeast has been isolated. The isolate was identified as Rhodotorula sp. strain MBH23 using ITS rRNA analysis. The results showed that the best carbon source for growth was glucose at 1.0% (w/v). The optimum acrylamide concentration, being a nitrogen source for cellular growth, was at 500 mg l(-1). The highest tolerable concentration of acrylamide was 1500 mg l(-1) whereas growth was completely inhibited at 2000 mg l(-1). At 500 mg l(-1), the strain MBH completely degraded acrylamide on day 5. Acrylic acid as a metabolite was detected in the media. Strain MBH23 grew well between pH 6.0 and 8.0 and between 27 and 30 °C. Amides such as 2-chloroacetamide, methacrylamide, nicotinamide, acrylamide, acetamide, and propionamide supported growth. Toxic heavy metals such as mercury, chromium, and cadmium inhibited growth on acrylamide.
  16. Isolation and characterization of an acrylamide-degrading Bacillus cereus
    Shukor MY, Gusmanizar N, Azmi NA, Hamid M, Ramli J, Shamaan NA, et al.
    J Environ Biol, 2009 Jan;30(1):57-64.
    PMID: 20112864
    Several local acrylamide-degrading bacteria have been isolated. One of the isolate that exhibited the highest growth on acrylamide as a nitrogen source was then further characterized. The isolate was tentatively identified as Bacillus cereus strain DRY135 based on carbon utilization profiles using Biolog GP plates and partial 16S rDNA molecular phylogeny. The isolate grew optimally in between the temperatures of 25 and 30 degrees C and within the pH range of 6.8 to 7.0. Glucose, fructose, lactose, maltose, mannitol, citric acid and sucrose supported growth with glucose being the best carbon source. Different concentrations of acrylamide ranging from 100 to 4000 mg l(-1) incorporated into the growth media shows that the highest growth was obtained at acrylamide concentrations of between 500 to 1500 mg l(-1). At 1000 mg l(-1) of acrylamide, degradation was 90% completed after ten days of incubation with concomitant cell growth. The metabolite acrylic acid was detected in the media during degradation. Other amides such as methacrylamide, nicotinamide, acetamide, propionamide and urea supported growth with the highest growth supported by acetamide, propionamide and urea. Strain DRY135, however was not able to assimilate 2-chloroacetamide. The characteristics of this isolate suggest that it would be useful in the bioremediation of acrylamide.
  17. Isolation and characterization of an acrylamide-degrading Antarctic bacterium
    Shukor MY, Gusmanizar N, Ramli J, Shamaan NA, MacCormack WP, Syed MA
    J Environ Biol, 2009 Jan;30(1):107-12.
    PMID: 20112871
    The presence of acrylamide in the environment poses a threat due to its well known neurotoxic, carcinogenic and teratogenic properties. Human activities in various geographical areas are the main anthropogenic source of acrylamide pollution. In this work, an acrylamide-degrading bacterium was isolated from Antarctic soil. The physiological characteristics and optimum growth conditions of the acrylamide-degrading bacteria were investigated. The isolate was tentatively identified as Pseudomonas sp. strain DRYJ7 based on carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. The results showed that the best carbon sources for growth was glucose and sucrose with no significant difference in terms of cellular growth between the two carbon sources (p>0.05). This was followed by fructose and maltose with fructose giving significantly higher cellular growth compared to maltose (p<0.05). Lactose and citric acid did not support growth. The optimum acrylamide concentration as a nitrogen source for cellular growth was at 500 mgl(-1). At this concentration, bacterial growth showed a 2-day lag phase before degradation took place concomitant with an increase in cellular growth. The isolate exhibited optimum growth in between pH 7.5 and 8.5. The effect of incubation temperature on the growth of this isolate showed an optimum growth at 15 degrees C. The characteristics of this isolate suggest that it would be useful in the bioremediation of acrylamide.
  18. Isolation and characterization of an SDS-degrading Klebsiella oxytoca
    Shukor MY, Husin WS, Rahman MF, Shamaan NA, Syed MA
    J Environ Biol, 2009 Jan;30(1):129-34.
    PMID: 20112874
    Sodium dodecyl sulfate (SDS) is one of the main components in the detergent and cosmetic industries. Its bioremediation by suitable microorganism has begun to receive greater attention as the amount of SDS usage increases to a point where treatment plants would not be able to cope with the increasing amount of SDS in wastewater. The purpose of this work was to isolate local SDS-degrading bacteria. Screening was carried out by the conventional enrichment-culture technique. Six SDS-degrading bacteria were isolated. Of these isolates, isolate S14 showed the highest degradation of SDS with 90% degradation after three days of incubation. Isolate S14 was tentatively identified as Klebsiella oxytoca strain DRY14 based on carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. SDS degradation by the bacterium was optimum at 37 degrees 0. Ammonium sulphate; at 2.0 g l(-1), was found to be the best nitrogen source for the growth of strain DRY14. Maximum growth on SDS was observed at pH 7.25. The strain exhibited optimum growth at SDS concentration of 2.0 g l(-1) and was completely inhibited at 10 g l(-1) SDS. At the tolerable initial concentration of 2.0 g l(-1), almost 80% of 2.0 g l(-1) SDS was degraded after 4 days of incubation concomitant with increase in cellular growth. The K(m(app) and V(max(app)) values calculated for the alkylsulfatase from this bacterium were 0.1 mM SDS and 1.07 micromol min(-1) mg(-1) protein, respectively.
  19. Isolation and characterization of a phenol-degrading Rhodococcus sp. strain AQ5NOL 2 KCTC 11961BP
    Arif NM, Ahmad SA, Syed MA, Shukor MY
    J Basic Microbiol, 2013 Jan;53(1):9-19.
    PMID: 22581645 DOI: 10.1002/jobm.201100120
    In this work, we report on the isolation of a phenol-degrading Rhodococcus sp. with a high tolerance towards phenol. The isolate was identified as Rhodococcus sp. strain AQ5NOL 2, based on 16S rDNA analysis. The strain degraded phenol using the meta pathway, a trait shared by many phenol-degraders. In addition to phenol biodegradation, the strain was also capable of degrading diesel. Strain AQ5NOL 2 exhibited a broad optimum temperature for growth on phenol at between 20 °C and 35 °C. The best nitrogen sources were ammonium sulphate, glycine or phenylalanine, followed by proline, nitrate, leucine, and alanine (in decreasing efficiency). Strain AQ5NOL 2 showed a high tolerance and degradation capacity of phenol, for it was able to register growth in the presence of 2000 mg l(-1) phenol. The growth of this strain on phenol as sole carbon and energy source were modeled using Haldane kinetics with a maximal specific growth rate (μ(max)) of 0.1102 hr(-1), a half-saturation constant (K(s) ) of 99.03 mg l(-1) or 1.05 mmol l(-1), and a substrate inhibition constant (K(i)) of 354 mg l(-1) or 3.76 mmol l(-1). Aside from phenol, the strain could utilize diesel, 2,4-dinitrophenol and ρ-cresol as carbon sources for growth. Strain AQ5NOL 2 exhibited inhibition of phenol degradation by Zn(2+), Cu(2+), Cr(6+), Ag(+) and Hg(2+) at 1 mg l(-1).
  20. Isolation and characterization of a Pseudomonas diesel-degrading strain from Antarctica
    Shukor MY, Hassan NA, Jusoh AZ, Perumal N, Shamaan NA, MacCormack WP, et al.
    J Environ Biol, 2009 Jan;30(1):1-6.
    PMID: 20112855
    A diesel-degrading bacterium from Antarctica has been isolated. The isolate was tentatively identified as Pseudomonas sp. strain DRYJ3 based on partial 16S rDNA molecular phylogeny and Biolog GN microplate panels and Microlog database. Growth on diesel was supported optimally by ammonium sulphate, nitrate and nitrite. The bacterium grew optimally in between 10 and 15 degrees C, pH 7.0 and 3.5% (v/v) diesel. The biodegradation of diesel oil by the strain increased in efficiency from the second to the sixth day of incubation from 1.4 to 18.8% before levelling off on the eighth day n-alkane oxidizing and aldehyde reductase activities were detected in the crude enzyme preparation suggesting the existence of terminal n-alkane oxidizing activity in this bacterium.
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