Biodegradation Of Diesel By A Locally Isolated Acinetobacter Sp.

Local bacteria isolated from oil-contaminated soils from various locations in Malaysia were screened for their ability to degrade commercial diesel fuel. Enrichment culture from soil samples yielded several isolates capable of degrading diesel. Of these, Isolate 1 was selected for further studies based on its best growth performance compared to the other isolates. Biodegradation studies were conducted using head-space solid-phase microextraction (HS-SPME: 110°C, 10 min, 7 μm PDMS fiber and 25% NaCl) coupled to gas chromatography equipped with flame ionization detector (GC-FID). The isolate was identified as Acinetobacter sp. (1470 bp) (98% sequence homology) using 16s rRNA molecular phylogenetic analysis. Isolate 1 exhibited optimum growth at 37°C in media containing 4% (v/v) diesel, and is able to degrade 51.7% of diesel in 6 days. Isolate 1 was grown on various nitrogen sources such as NH4Cl, NH4SO4, NaNO3, and KNO3. The best nitrogen source is potassium nitrate (KNO3) at 0.9% (v/v). Its optimized optimum pH for growth is pH 7.5. Five different diesel-degrading enzymes were detected: alkane-oxidizing enzyme (0.2.8 μmol min-1 ml-1), alcohol dehydrogenase (9.0956 μmol min-1 ml-1), aldehyde dehydrogenase (4.234 μmol min-1 ml-1), pyridine nucleotide-independent dehydrogenase (4.229 μmol min-1 ml-1) and aldehyde reductase (8.126 μmol min-1 ml-1

Penyingkiran racun siput gondang emas menggunakan granulasi aerobik (Removal of Gondang Emas Pesticide using Aerobic Granulation) / Azlina Mat Saad … [et al.]

Peningkatan jumlah populasi siput gondang emas dalam sawah padisecara langsung telah meningkatkan penggunaan racun perosak iaitu metaldehyde. Sisa racun perosak yang telah digunakan akan berakhir di dalam sistem air yang merupakan sumber air dan habitat kepada hidupan akuatik. Manusia dan haiwan lain turut menerima impak negatif dengan pencemaran ini. Sisa racun terkumpul di dalam badan mampu merosakkan sistem saraf dan hati. Sebagai penyelesaian, kajian ini akan memantau keupayaan granul aerobik untuk menyingkirkan metaldehyde dari air sisa.Sebuah bioreaktor yang dikenali sebagai reaktor kumpulan penjujukan telah digunakan untuk membangunkan butiran aerobik. Sampel enapcemar diaktifkan diambil dari loji rawatan air sisa telah digunakan sebagai enapcemar benih untuk memulakan pembentukan granul aerobik.Biomas dalam enapcemar benih diberi makan air sisa sintetik yang terdiri daripada beberapa bahan kimia sebagai sumber karbon dan nutrien

Characteristics of developed granules containing phototrophic aerobic bacteria for minimizing carbon dioxide

Aerobic wastewater treatment has contributed to the greenhouse gases (GHG) emission in the atmosphere, which can cause global warming. The GHG consists of six major gases particularly carbon dioxide (CO2). Existing biological system of the wastewater treatment needs to be reviewed in order to minimize the emission of GHG especially CO2. Some findings had shown that photosynthetic bacteria can be employed for CO2 utilization during the wastewater treatment processes. The aim of this study was to characterize phototrophic microbial granule in order to minimize CO2. Synthetic wastewater was used throughout this study to obtain the aerobic granules. A 3-L bioreactor phototrophic Sequencing Batch Reactor (SBRP) was applied to produce phototrophic aerobic granular sludge (AGSP) and the biomass concentration increased from 3 to 14gL-1. Such growth has resulted in a maximum settling velocity of 40mh-1 with granule average size of ~ 2.0mm. The high settling velocity was found to be attributed by the smooth, compact, and regular characteristics of the aerobic granules. High magnification microscopic analysis revealed that AGSP was dominated by cocci-shaped bacteria embedded within the extracellular polymeric substances (EPS). Detailed observation on the structure of the AGSP showed the presence of 30µm of cavity to allow nutrients and gas exchanges within the aerobic granule. Scanning Electron Microscope-Energy-Dispersive X-ray (SEM-EDX) examination showed AGSP composed of different types of inorganic and organic compounds. AGSP achieved 92% of CO2 reduction and 84% of chemical oxygen demand (COD) removal

Characterization of a diesel-degrading strain isolated from a hydrocarbon-contaminated site

A diesel-degrading bacterium has been isolated from a diesel-polluted site. The isolate was tentatively identified as Staphylococcus aureus strain DRY11 based on partial 16S rDNA molecular phylogeny and Biolog® GP microplate panels and Microlog® database. Isolate 11 showed an almost linear increase in cellular growth with respect to diesel concentrations with optimum growth occurring at 4% (v/v) diesel concentration. Optimization studies using different nitrogen sources showed that the best nitrogen source was potassium nitrite. Sodium nitrite was optimum at 1.2 g l-1 and higher concentrations were strongly inhibitory to cellular growth. The optimal pH that supported growth of the bacterium was between 7.5 to 8.0 and the isolate exhibited optimal broad temperature supporting growth on diesel from 27 to 37 °C. An almost complete removal of diesel components was seen from the reduction in hydrocarbon peaks observed using Solid Phase Microextraction Gas Chromatography analysis after 5 days of incubation. The characteristics of this bacterium suggest that it is suitable for bioremediation of diesel spills and pollutions in the tropics

Mathematical modeling of molybdenum blue production from Serratia marcescens strain DR.Y10

The pollution of heavy metals and toxic xenobiotics has become a central issue worldwide. Bioremediation of these toxicants are being constantly carried out using novel microbes. Molybdenum reduction to molybdenum blue is a detoxification process and mathematical modelling of the reduction process can reveal important parameters such as specific reduction rate, theoretical maximum reduction and whether reduction at high molybdenum concentration affected the lag period of reduction. The used of linearization method through the use of natural logarithm transformation, although popular, is inaccurate and can only give an approximate value for the sole parameter measured; the specific growth rate. In this work, a variety of models for such as logistic, Gompertz, Richards, Schnute, Baranyi-Roberts, Von Bertalanffy, Buchanan three-phase and more recently Huang were utilized for the first time to obtain values for the above parameters or constants. The modified Gompertz model was the best model in modelling the Mo-blue production curve from Serratia marcescens strain DR.Y10 based on statistical tests such as root-mean-square error (RMSE), adjusted coefficient of determination (R2), bias factor (BF), accuracy factor (AF) and corrected AICc (Akaike Information Criterion). Parameters obtained from the fitting exercise were maximum Mo-blue production rate (um), lag time (l) and maximal Mo-blue production (Ymax) of X (h-1), Y (h) and Z (nmole Mo-blue), respectively. The application of primary population growth models in modelling the Mo-blue production rate from this bacterium has become a successful undertaking. The model may also be used in other heavy metals detoxification processes. The parameters constants extracted from this work will be a substantial help for the future development of further secondary models

Evaluation of Water Hyacinth (Eichhornia crassipes) as a Potential Raw Material Source for Briquette Production

In the present study we investigated the fuel properties of bio-briquettes made from a combination of water hyacinth and empty fruit bunch fiber (palm oil mill residue). Water hyacinth (WH) was mixed with empty fruit bunch (EFB) fibers in a ratio of 25, 50, 75, 90, and 100% by weight and cassava starch added as binder. The experimental results showed that the addition of WH had a little effect (p < 0.05) on the physical and combustion properties of the briquettes. The proximate analysis showed that the moisture content, ash content and fixed carbon content were increased with the increase in WH amount from 25 to 100%, while the volatile matter content and calorific value decreased. Combustion test showed that the increase in the WH percentage in bio-briquette resulted in the decreased of O2 and CO level, whereas, that of CO2 and NO, NO2 and SO2 were increased. Therefore, the results conclude that the WH: EFB biomass bio-briquette could be a great potential as an alternative source to conventional coal to minimize the emission of greenhouse gases

Acetylcholinesterase from Puntius javanicus for the detection of carbamate and organophosphate

A new alternative local source of acetylcholinesterase (AChE) has been found to be sensitive towards several insecticides. AChE was purified from the brain tissue of Puntius javanicususing affinity chromatography (procainamide hydrochloride coupled with sephacryl 6B) with the total recovery of 40% at 8.48 purification fold. All carbamate (CB) insecticides tested at the concentration of 1 mg/L were capable of lowering AChE activity to less than 30%; Bendiocarp (18.80%), carbaryl (5.96%,), carbofuran (6.12%), methomyl (13.91%) and propoxur (15.851%). The P. javanicus AChE was found to be unaffected by several activated organophosphates (OP) such as acephate and dimethoate, while trichlorfon slightly inhibited the enzyme activity (p<0.05). Chlorpyrifos, diazinon, malathion and parathion lowered AChE activity to 43.02, 40.97, 37.11 and 46.72%, respectively. Pesticides that inhibit AChE activities more than 50% were further tested in different concentrations to determine the half maximal inhibitory concentration (IC50). Carbofuran and carbaryl showed the lowest IC50 value at 0.035 and 0.031 mg/L, respectively, as both showed no significant differences (p <0.05), followed by bendiocarp, propoxur, methomyl, malathion, diazinon, parathion and chlorpyrifos at 0.045, 0.076, 0.090, 0.063, 0.103, 0.151 and 0.202 mg/L, respectively. Based on these results, the sensitivity of AChE from brain P. javanicus brain tissue shows promise as an alternative biosensor for the detection of insecticides contamination

Isolation and characterization of a molybdenum-reducing and amide-degrading Burkholderia sp. strain NENI-11 in soils from West Sumatra, Indonesia

A molybdenum-reducing bacterium isolated from contaminated soil was able to utilize acrylamide as the electron donor source, and was able utilize acrylamide, acetamide and propionamide for growth. Reduction was optimal at pH between 6.0 to 6.3, at temperatures of between 30 and 37 oC, glucose as the electron donor, phosphate at 5.0 mM, and sodium molybdate at 15 mM. The absorption spectrum of the Mo-blue indicates it is a reduced phosphomolybdate. Molybdenum reduction was inhibited by mercury (ii), silver (i) and chromium (vi) at 2 p.p.m. by 91.9, 82.7 and 17.4 %, respectively. Biochemical analysis resulted in a tentative identification of the bacterium as Burkholderia cepacia strain Neni-11. The growth of this bacterium modelled according to the modified Gompertz model. The growth parameters obtained were maximum specific growth rates of 1.241 d-1, 0.971 d-1, 0.85 d-1 for acrylamide, propionamide and acetamide, respectively, while the lag periods of 1.372 d, 1.562 and 1.639 d were observed for acrylamide, propionamide and acetamide, respectively. The ability of this bacterium to detoxify molybdenum and grown on toxic amides makes this bacterium an important tool for bioremediation

Acetylcholinesterase from Puntius javanicus for the detection of carbamates and organophosphates

A new alternative local source of acetylcholinesterase (AChE) has been found to be sensitive towards several insecticides. AChE was purified from the brain tissue of Puntius javanicususing affinity chromatography (procainamide hydrochloride coupled with sephacryl 6B) with the total recovery of 40% at 8.48 purification fold. All carbamate (CB) insecticides tested at the concentration of 1 mg/L were capable of lowering AChE activity to less than 30%; Bendiocarp (18.80%), carbaryl (5.96%,), carbofuran (6.12%), methomyl (13.91%) and propoxur (15.851%). The P. javanicus AChE was found to be unaffected by several activated organophosphates (OP) such as acephate and dimethoate, while trichlorfon slightly inhibited the enzyme activity (p<0.05). Chlorpyrifos, diazinon, malathion and parathion lowered AChE activity to 43.02, 40.97, 37.11 and 46.72%, respectively. Pesticides that inhibit AChE activities more than 50% were further tested in different concentrations to determine the half maximal inhibitory concentration (IC50). Carbofuran and carbaryl showed the lowest IC50 value at 0.035 and 0.031 mg/L, respectively, as both showed no significant differences (p<0.05), followed by bendiocarp, propoxur, methomyl, malathion, diazinon, parathion and chlorpyrifos at 0.045, 0.076, 0.090, 0.063, 0.103, 0.151 and 0.202 mg/L, respectively. Based on these results, the sensitivity of AChE from brain P. javanicus brain tissue shows promise as an alternative biosensor for the detection of insecticides contamination

Optimization of Aloe vera and alginate as encapsulating matrices for Lactobacillus acidophilus using FCCD-RSM approach

In order to maintain the viability of probiotic, the used of prebiotic is important. Aloe vera has been hypothesized to be a prebiotic potential for probiotic. Due to low viability of encapsulated cells, Aloe vera gel was used to be part of enacapsulating matrices for probioctic, Lactobacillus acidophilus. As a result, optimization of Aloe vera gel with sodium alginate was carried out in order to determine the maximum encapsulation yield. Face centered composite design-response surface methodology (FCCD-RSM) was employed to optimize the sodium alginate concentration and Aloe vera gel (prebiotic) composition during microencapsulation process in performing a better encapsulation yield for L. acidophilus. The encapsulation yield (EY) of encapsulated L. acidophilus was investigated with respect to two variables which were sodium alginate (X1) and Aloe vera gel (X2). Result obtained with polynomial regression model used in this study showed highly significant (0.0013) with R2 value was 0.9138. Aloe vera gel was showed highly significant (p<0.05) effect to the encapsulation yield. The optimum Aloe vera gel and sodium alginate were obtained at 1.12% (v/v) and 1.28% (w/v), respectively. Based on the verification process, the experimental and predicted results were showed not significant difference (p< 0.05)