The main objective of the study was to determine the biodegradability, resorption and osteoconductivity potency of coral implant. Coral blocks (CORAGRAF) were prepared from sea coral Porites species. The blocks were implanted in the right mandible of rabbit model. Implants were harvested at 2 and 4 weeks intervals and subjected for light and scanning electron microscopy. Dense hydroxyapatite (DHA) was implanted in the left mandible as a control. The results of this study demonstrated that CORAGRAF is a good implant material that can accelerates bone healing and be resorbed in an acceptable time. The mechanisms of the resorption seemed to be the same (crumbling process), a first step where the edge of the coral become powdery then a second step which could be phagocytosis and dissolution in extracellular fluid.
A Rhodococcus sp. UKMP-5M isolate was shown to detoxify cyanide successfully, suggesting the presence of an intrinsic property in the bacterium which required no prior cyanide exposure for induction of this property. However, in order to promote growth, Rhodococcus sp. UKMP-5M was fully acclimatized to cyanide after 7 successive subcultures in 0.1 mM KCN for 30 days. To further shorten the lag phase and simultaneously increase the tolerance towards higher cyanide concentrations, the bacterium was induced with various nitrile compounds sharing a similar degradatory pathway to cyanide. Acetonitrile emerged as the most favored inducer and the induced cells were able to degrade 0.1 mM KCN almost completely within 18 h. With the addition of subsequent aliquots of 0.1 mM KCN a shorter period for complete removal of cyanide was required, which proved to be advantageous economically. Both resting cells and crude enzyme of Rhodococcus sp. UKMP-5M were able to biodegrade cyanide to ammonia and formate without the formation of formamide, implying the identification of a simple hydrolytic cyanide degradation pathway involving the enzyme cyanidase. Further verification with SDS-PAGE revealed that the molecular weight of the active enzyme was estimated to be 38 kDa, which is consistent with previously reported cyanidases. Since the recent advancement in the application of biological methods in treating cyanide-bearing wastewater has been promising, the discovery of this new bacterium will add value by diversifying the existing microbial populations capable of cyanide detoxification.
Prazosin (PRZ), a drug used to treat hypertensive patients, is an emergent contaminant in water systems. PRZ is an alpha-adrenergic receptor blocker used to treat anxiety, and is believed to reach the environment through human excretion, irresponsible disposal of unused medicine, and waste products from manufacturing plants. The purpose of this research was to isolate and characterize potential microbes for PRZ biodegradation and to identify the degradation pathway. After screening, isolated strain STP3 showed a capability for PRZ degradation and was chosen for further analysis. Resting cell assays with PRZ were conducted to identify the intermediate metabolites formed from biodegradation by Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) analysis. Two metabolites degraded from PRZ by STP3 were successfully found, and as these metabolites are derived from the main structure of PRZ, their presence proved PRZ degradation. Draft genome sequencing analysis of STP3 was performed to identify potential enzymes for PRZ biodegradation based on the metabolites found.
Arthrobacter alpinus R3.8 is a psychrotolerant bacterial strain isolated from a soil sample obtained at Rothera Point, Adelaide Island, close to the Antarctic Peninsula. Strain R3.8 was sequenced in order to help discover potential cold active enzymes with biotechnological applications. Genome analysis identified various cold adaptation genes including some coding for anti-freeze proteins and cold-shock proteins, genes involved in bioremediation of xenobiotic compounds including naphthalene, and genes with chitinolytic and N-acetylglucosamine utilization properties and also plant-growth-influencing properties. In this genome report, we present a complete genome sequence of A. alpinus strain R3.8 and its annotation data, which will facilitate exploitation of potential novel cold-active enzymes.
The fluctuation of domestic wastewater characteristic inhibits the current conventional microbial-based treatment. The bioremediation fungi has received attention and reported to be an effective alternative to treat industrial wastewater. Similar efficient performance is envisaged for domestic wastewater whereby assessed performance of fungi for varying carbon-to-nitrogen ratios in domestic wastewater is crucial. Thus, the performance of pre-grown wild-Serbian Ganoderma lucidum mycelial pellets (GLMPs) was evaluated on four different synthetic domestic wastewaters under different conditions of initial pH (pH 4, 5, and 7) and chemical oxygen demand (COD) to nitrogen (COD/N) ratio of 3.6:1, 7.1:1, 14.2:1, and 17.8:1 (C3.6N1, C7.1N1, C14.2N1, and C17.8N1). The COD/N ratios with a constant concentration of ammonia-nitrogen (NH3-N) were chosen on the basis of the urban domestic wastewater characteristics sampled at the inlet basin of a sewage treatment plant (STP). The parameters of pH, COD, and NH3-N were measured periodically during the experiment. The wild-Serbian GLMPs efficiently removed the pollutants from the synthetic sewage. The COD/N ratio of C17.8N1 wastewater had the best COD and NH3-N removal, as compared to the lower COD/N ratio, and the shortest treatment time was obtained in an acidic environment at pH 4. The highest percentage for COD and NH3-N removal achieved was 96.0% and 93.2%, respectively. The results proved that the mycelium of GLMP has high potential in treating domestic wastewater, particularly at high organic content as a naturally sustainable bioremediation system.
Phytoremediation is one of the environmental-friendly and cost-effective systems for the treatment of wastewater, including industrial wastewater such as palm oil mill effluent final discharge (POME FD). However, the effects of the wastewater on the phytoremediator plants, in term of growth performance, lignocellulosic composition, and the presence of nutrients and heavy metals in the plants are not yet well studied. In the present work, we demonstrated that POME FD increased the growth of P. purpureum. The height increment of P. purpureum supplied with POME FD (treatment) was 61.72% as compared to those supplied with rain water (control) which was 14.42%. For lignocellulosic composition, the cellulose percentages were 38.77 ± 0.29% (treatment) and 34.16 ± 1.01% (control), and the difference was significant. These results indicated that POME FD could be a source of plant nutrients, which P. purpureum can absorb for growth. It was also found that the heavy metals (Al, As, Cd, Co, Cr, Ni and Pb) inside the plant were below the standard limit of the World Health Organization (WHO). Since POME FD was shown to have no adverse effects on P. purpureum, further research regarding the potential application of P. purpureum following phytoremediation of POME FD such as biofuel production is warranted to evaluate its potential use to fit into the waste-to-wealth agenda.
Odors due to the emission of hydrogen sulfide (H2S) have been a concern in the sewage treatment plants over the last decades. H2S fate and emissions from extended aeration activated sludge (EAAS) system in Muharram Aisha-sewage treatment plant (MA-STP) were studied using TOXCHEM model. Sensitivity analysis at different aeration flowrate, H2S loading rate, wastewater pH, wastewater temperature and wind speed were studied. The predicted data were validated against actual results, where all the data were validated within the limits, and the statistical evaluation of normalized mean square error (NMSE), geometric variance (VG), and correlation coefficient (R) were close to the ideal fit. The results showed that the major processes occurring in the system were degradation and emission. During summer (27 °C) and winter (12 °C), about 25 and 23%, 1 and 2%, 2 and 2%, and 72 and 73% were fated as emitted to air, discharged with effluent, sorbed to sludge, and biodegraded, respectively. At summer and winter, the total emitted concentrations of H2S were 6.403 and 5.614 ppm, respectively. The sensitivity results indicated that aeration flowrate, H2S loading rate and wastewater pH highly influenced the emission and degradation of H2S processes compared to wastewater temperature and wind speed. To conclude, TOXCHEM model successfully predicted the H2S fate and emissions in EAAS system.
The conversion of lignocellulosic biomass into bioethanol or biochemical products requires a crucial pretreatment process to breakdown the recalcitrant lignin structure. This research focuses on the isolation and characterization of a lignin-degrading bacterial strain from a decaying oil palm empty fruit bunch (OPEFB). The isolated strain, identified as Streptomyces sp. S6, grew in a minimal medium with Kraft lignin (KL) as the sole carbon source. Several known ligninolytic enzyme assays were performed, and lignin peroxidase (LiP), laccase (Lac), dye-decolorizing peroxidase (DyP) and aryl-alcohol oxidase (AAO) activities were detected. A 55.3% reduction in the molecular weight (Mw) of KL was observed after 7 days of incubation with Streptomyces sp. S6 based on gel-permeation chromatography (GPC). Gas chromatography-mass spectrometry (GC-MS) also successfully highlighted the production of lignin-derived aromatic compounds, such as 3-methyl-butanoic acid, guaiacol derivatives, and 4,6-dimethyl-dodecane, after treatment of KL with strain S6. Finally, draft genome analysis of Streptomyces sp. S6 also revealed the presence of strong lignin degradation machinery and identified various candidate genes responsible for lignin depolymerization, as well as for the mineralization of the lower molecular weight compounds, confirming the lignin degradation capability of the bacterial strain.
Most components of petroleum oily sludge (POS) are toxic, mutagenic and cancer-causing. Often bioremediation using microorganisms is hindered by the toxicity of POS. Under this circumstance, phytoremediation is the main option as it can overcome the toxicity of POS. Cajanus cajan a legume plant, was evaluated as a phyto-remediating agent for petroleum oily sludge-spiked soil. Culture dependent and independent methods were used to determine the rhizosphere microorganisms' composition. Degradation rates were estimated gravimetrically. The population of total heterotrophic bacteria (THRB) was significantly higher in the uncontaminated soil compared to the contaminated rhizosphere soil with C. cajan, but the population of hydrocarbon-utilizing bacteria (HUB) was higher in the contaminated rhizosphere soil. The results show that for 1 to 3% oily sludge concentrations, an increase in microbial counts for all treatments from day 0 to 90 d was observed with the contaminated rhizosphere CR showing the highest significant increase (p
Complete genomes of xenobiotic-degrading microorganisms provide valuable resources for researchers to understand molecular mechanisms involved in bioremediation. Despite the well-known ability of Sphingomonas paucimobilis to degrade persistent xenobiotic compounds, a complete genome sequencing is lacking for this organism. In line with this, we report the first complete genome sequence of Sphingomonas paucimobilis (strain AIMST S2), an organophosphate and hydrocarbon-degrading bacterium isolated from oil-polluted soil at Kedah, Malaysia. The genome was derived from a hybrid assembly of short and long reads generated by Illumina HiSeq and MinION, respectively. The assembly resulted in a single contig of 4,005,505 bases which consisted of 3,612 CDS and 56 tRNAs. An array of genes involved in xenobiotic degradation and plant-growth promoters were identified, suggesting its' potential role as an effective microorganism in bioremediation and agriculture. Having reported the first complete genome of the species, this study will serve as a stepping stone for comparative genome analysis of Sphingomonas strains and other xenobiotic-degrading microorganisms as well as gene expression studies in organophosphate biodegradation.
Mixed microbial culture used in this study was developed from sludge that was taken from local textile wastewater treatment tank. Acclimatization process was performed before starting the biodegradation experiment to obtain a microbial culture with high degradation properties. Kinetic studies by the mixed microbial culture were determined quantitatively for the model pollutant, Reactive Black 5 (RB 5). By using Michaelis-Menten model, the constants were found to be 11.15 mg l-1 h -1 and 29.18 mg l-1 for Vm and Km respectively. The values of kinetic constants for Monod model were found to be 33.11 mg l-1 cell h-1 for the maximum specific microbial growth rate, µm and 86.62 mg l-1 for Monod constant, Ks. The effects of process parameters such as pH, inoculum size and initial dye concentration on the biodegradation of azo dye, RB 5 were systematically investigated. Maximum removal efficiencies observed in this study were 75% for pH 6, 100% for 15% inoculum concentration and 75% for 20 ppm of initial dye concentration.
The concern on the widespread use of surfactants is increasing worldwide as they can be potential toxicants by polluting
the environment, with the damage formed depending on their exposure and persistence in the ecosystem. This paper
was intended to evaluate the biodegradability of palm-based surfactant, MES, in order to establish their environmental
friendliness. The respirometric method was used to monitor the biodegradation of various homologues of MES over 28
days as described in the OECD 301F Manometric respirometry test method. The results showed all the MES homologues
tested were readily biodegradable with percentage of biodegradation achieved for C12, C14 and C16 MES was 73%
within 6 days, 66% within 8 days and 63% within 16 days, respectively, while linear alkylbenzene sulphonates (LAS)
sample 60% biodegraded within 8 days. From the results, it can be concluded that the longer the carbon chain length, the
lower is the biodegradability of MES as the microorganisms took longer time to degrade a longer chain surfactant. Other
than that, the presence of aromatic structure in LAS may also extend the biodegradation process. The use of palm-based
surfactant, i.e. MES, is more environmental friendly and can be used as an alternative to petroleum-based surfactant to
reduce adverse environmental effects of surfactant on ecosystem.
Heavy metal pollution leads to human health problems and represents a constant threat to the environment. Pollutant
clean-up using conventional methods are often hampered by high cost and ineffective pollutant removal. Phytoremediation
technique is a preferable alternative due to its minimal side effects to the environment in addition to reasonable treatment
cost. In this study, we investigated the potential of Centella asiatica and Orthosiphon stamineus as phytoremediation
agents. Both species were grown in contaminated soil obtained from industrial land. Plant growth response and their
ability to accumulate and translocate zinc, copper and lead were assessed. From this study, root growth of C. asiatica
was compromised when grown in contaminated soil. Copper was highly accumulated in C. asiatica roots while the
leaves were more concentrated with zinc and lead. Conversely, all three tested metals were highly detected in the roots
of O. stamineus, although the root elongation was not adversely affected. Low amount of metals in the stems of both
species permits longer stem length. Correlation study showed that the accumulation of zinc, copper and lead in plant
tissues varies depending on plant species and the type of metals. Based on the bioaccumulation, translocation and
enrichment factor, our study showed that C. asiatica was tolerant towards zinc, copper and lead; hence suitable for
phytoextraction. By contrast, O. stamineus acted as a moderate accumulator of the tested metal elements.
Biosurfactants are microbially produced surface active agents that offer better biodegradability and lower toxicity than chemically synthesized surfactants because of their biogenetic origin. One of the most surface-active biosurfactants known is surfactin, a cyclic lipopeptide produced by various strains of Bacillus subtilis. In this study, the cleaning potential of surfactin on ultrafiltration (UF) membranes fouled with BSA was studied using centrifugal UF devices of 50 kDa and 100 kDa MWCO polyethersulfone (PES) membranes. Mechanisms of bovine serum albumin (BSA) displacement by surfactin on fouled UF membranes were studied using dynamic light scattering (DLS) technique and surface tension measurements. Hydrodynamic diameter and surface tension measurements of BSA-surfactin mixtures showed that the surfactin was efficient in displacing BSA fouled on UF membranes due to strong electrostatic repulsive interactions involved at pH8.5. This study demonstrated that surfactin can be used to effectively clean fouled UF membranes.
In the present study, capability of water hyacinth in removing heavy metals such as Cadmium (Cd), Chromium (Cr), Copper (Cu), Zinc (Zn), Iron (Fe), and Boron (B) in ceramic wastewater was investigated. The metal removal efficiency was identified by evaluating the translocation of metals in roots, leaves and shoot of water hyacinth. The heavy metal removal efficiency followed the order Fe>Zn>Cd>Cu>Cr>B during the treatment process. Water hyacinth had luxury consumption of those 6 elements. This study used the circulation system with 3 columns of plants which functioned as bioremediation of the sample. The concentration of metals in roots is much higher 10 times than leaves and stems. Roots give the result of metalR>metalL. The removal concentration from water hyacinth was estimated under pH of 8.21 to 8.49. This study proves water hyacinth to be a best plant for phytoremediation process
Bioremediation of crude oil using biostimulation and/or bioaugmentation was done by simulation study in the green house under uncontrolled environment temperature. In this study, the soil with indigenous microbes was spiked with Tapis crude oil at 200 g/kg. The microbial density of the amended soils was augmented by addition of fresh inoculum of microbial consortium which consist of Pseudomonas aeruginosa UKMP-14T, Acinetobacter baumannii UKMP-12T and seed culture two strains of fungi, Trichoderma virens UKMP-1M and Trichoderma virens UKMP-2M at ratio 1:1:1:1 (v/w). The amendment soil was added with 20% (v/w) of standardize consortium inoculum, 20% (w/w) of dried empty fruit bunch (EFB) and the effect of EFB was compared with 0.7% commercial fertilizer (v/w) which contain NPK (8:8:1). Soil with indigenous microbes was used as a control. Results showed total petroleum hydrocarbon (TPH) degradation for treatment added with NPK fertilizer was 70.36%, addition with EFB bulking agent 68.86% and addition of both NPK and EFB was 100% at day 30 of incubation. The control plot, 62% of TPH degradation was achieved after 30 days incubation.
Cyanide is highly toxic to the living organisms as it inhibits respiration system in the cell mitochondria. Cyanide is commonly used in gold extraction process and its discharge into the environment not only causes pollution but it also brings harm to the surrounding population. Chemical treatment is expensive and the use of hazardous compound can exacerbate the problem. Biodegradation offers cheap and safe alternative as it overcomes the problems faced by chemical treatment. In this study, indigenous bacteria from mining wastewater were isolated. Cyanide degradation was done via shake flask method. A bacterium, designated W2 was found able to grow in the mining wastewater. 16S rRNA analysis identified the strain as Pseudomonas pseudoalcaligenes which could tolerate up to 39 mg/L cyanide concentration and growth was depleted at 52 mg/L. 60% cyanide degradation was achieved in wastewater containing medium. End-product analysis from high performance liquid chromatography (HPLC) detected formamide implicating the role of cyanide hydratase in cyanide degradation. It can be concluded that P. pseudoalcaligenes is capable of biodegrading cyanide and its potential in wastewater treatment containing cyanide is feasible.
Algae have recently received a lot of attention as a new biomass source for the production of renewable energy and an important bioremediation agent. This study was carried out to evaluate the potential of green algae Scenedesmus obliquus grow in different concentrations of wastewater and the improvement of cultivation conditions to produce biomass rich in sugar to produce bioethanol by fermentation processes. The highest sugar content of S. obliquus biomass was recorded for algae cultivated with 40 and 85% wastewater after 9 days under aeration condition with dark and light duration (44.5%). It was found that the highest removal efficiency of BOD and COD were 18% for S. obliquus grown under aeration condition. The highest ethanol efficiency of S. obliquus biomass hydrolysate was 20.33% at 4th day. The best condition of S. obliquus to grow efficiently was under aeration with light and dark durations, where it has high efficiency to remove heavy metals from wastewater in this condition.