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  1. Hydrogen fluoride (HF) substance flow analysis for safe and sustainable chemical industry
    Kim J, Hwang Y, Yoo M, Chen S, Lee IM
    Environ Sci Pollut Res Int, 2017 Nov;24(32):25137-25145.
    PMID: 28924945 DOI: 10.1007/s11356-017-0152-6
    In this study, the chemical substance flow of hydrogen fluoride (hydrofluoric acid, HF) in domestic chemical industries in 2014 was analyzed in order to provide a basic material and information for the establishment of organized management system to ensure safety during HF applications. A total of 44,751 tons of HF was made by four domestic companies (in 2014); import amount was 95,984 tons in 2014 while 21,579 tons of HF was imported in 2005. The export amount of HF was 2180 tons, of which 2074 ton (China, 1422 tons, U.S. 524 tons, and Malaysia, 128 tons) was exported for the manufacturing of semiconductors. Based on the export and import amounts, it can be inferred that HF was used for manufacturing semiconductors. The industries applications of 161,123 tons of HF were as follows: manufacturing of basic inorganic chemical substance (27,937 tons), manufacturing of other chemical products such as detergents (28,208 tons), manufacturing of flat display (24,896 tons), and manufacturing of glass container package (22,002 tons). In this study, an analysis of the chemical substance flow showed that HF was mainly used in the semiconductor industry as well as glass container manufacturing. Combined with other risk management tools and approaches in the chemical industry, the chemical substance flow analysis (CSFA) can be a useful tool and method for assessment and management. The current CSFA results provide useful information for policy making in the chemical industry and national systems. Graphical abstract Hydrogen fluoride chemical substance flows in 2014 in South Korea.
    Matched MeSH terms: Chemical Industry*
  2. A short review of activated carbon assisted electrosorption process: an overview, current stage and future prospects
    Foo KY, Hameed BH
    J Hazard Mater, 2009 Oct 30;170(2-3):552-9.
    PMID: 19501461 DOI: 10.1016/j.jhazmat.2009.05.057
    Stepping into the new globalizes and paradigm shifted era, a huge revolution has been undergone by the electrochemical industry. From a humble candidate of the superconductor resources, today electrosorption has demonstrated its wide variety of usefulness, almost in every part of the environmental conservation. With the renaissance of activated carbon (AC), there has been a steadily growing interest in this research field. The paper presents a state of art review of electrosorption technology, its background studies, fundamental chemistry and working principles. Moreover, recent development of the activated carbon assisted electrosorption process, its major challenges together with the future expectation are summarized and discussed. Conclusively, the expanding of electrosorption in the field of adsorption science represents a potentially viable and powerful tool, leading to the superior improvement of pollution control and environmental preservation.
    Matched MeSH terms: Chemical Industry/trends*
  3. Reduced metals concentrations of water, sediment and hyalella azteca from lakes in the vicinity of the sudbury metal smelters, Ontario, Canada
    Shuhaimi-Othman M, Pascoe D, Borgmann U, Norwood WP
    Environ Monit Assess, 2006 Jun;117(1-3):27-44.
    PMID: 16917696
    Hyalella azteca (Crustacea: Amphipoda), water and sediments from 12 circum-neutral lakes between Sudbury and North Bay in Ontario, Canada were sampled in August 1998 and analyzed for 10 metals including Cu, Zn, Cd, Ni, Pb, Co, Mo, V, Ba and Ti. Statistical analyses showed that concentrations of the metals in H. azteca, water and sediment differed significantly (ANOVA, P<0.05) among lakes (except for Zn and Pb in H. azteca and Mo in water). There was a trend of declining metal concentration, especially for Cu, Ni and Co (in water, Hyalella and sediment), with distance from the smelters indicating the reduced impact of atmospheric pollution. Metal concentrations of lakes (water) in the Sudbury area were found to be lower compared to data from the 1970s and 1980s indicating an improvement in water quality. Metal concentrations in field-collected amphipods compared favorably with those measured in the laboratory in animals exposed to deep-water sediments, provided metal concentrations were not extremely low (e.g., Pb) and that water chemistry differences (e.g., pH) were taken into account for some metals (especially Cd). In general bioaccumulation of metals in H. azteca was predicted better from surface water than from sediment total metal.
    Matched MeSH terms: Chemical Industry*
  4. An assessment of the concentrations of particulate polycyclic aromatic hydrocarbons (PAHs) in the aftermath of a chemical store fire incident
    Abas MR, Omar NY, Maah MJ
    J Environ Sci (China), 2004;16(5):751-4.
    PMID: 15559805
    PM10 airborne particles and soot deposit collected after a fire incident at a chemical store were analyzed in order to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs). The samples were extracted with 1:1 hexane-dichloromethane by ultrasonic agitation. The extracts were then subjected to gas chromatography-mass spectrometric (GC-MS) analysis. The total PAHs concentrations in airborne particles and soot deposit were found to be 3.27 +/- 1.55 ng/m3 and 12.81 +/- 24.37 microg/g, respectively. Based on the molecular distributions of PAHs and the interpretation of their diagnostic ratios such as PHEN/(PHEN + ANTH), FLT/(FLT + PYR) and BeP/(BeP + BaP), PAHs in both airborne particles and soot deposit may be inferred to be from the same source. The difference in the value of IP/(IP + BgP) for these samples indicated that benzo[g, h, i] perylene and coronene tend to be attached to finer particles and reside in the air for longer periods. Comparison between the molecular distributions of PAHs and their diagnostic ratios observed in the current study with those reported for urban atmospheric and roadside soil particles revealed that they are of different sources.
    Matched MeSH terms: Chemical Industry*
  5. Fulltext Conformity to occupational safety and health regulations in small and medium enterprises
    Baba Md Deros, Ahmad Rasdan Ismail, Mohd Yusri Mohd Yusof
    Journal of Occupational Safety and Health, 2012;9(1):1-6.
    MyJurnal
    Regulation on occupational safety and health in Malaysia had evolved from the prescriptive Factory and Machinery Act (1967) to a self-regulated Occupational Safety and Health Act (1994). However, from the authors’ observation the high standards of occupational safety and health culture that surpass the legal requirement were not widely practiced by small and medium enterprises (SMEs). The two main objectives of this study are: first, to identify and determine the level of conformity; and second, to investigate the reasons of nonconformity to Occupational Safety and Health Act (1994) regulation in SMEs involved the chemical industry sub-sectors. The survey questionnaire was distributed to 150 SMEs in chemical industry sub-sectors. Forty one of the survey questionnaires were completed and returned, giving a response rate of 27.3% for the survey. The survey results revealed that an overwhelming majority (92.7%) of the respondents from SMEs are likely not conforming to the basic requirement of Occupational Safety and Health Act (1994). In addition to this, the survey also found that only 3.1% of the management personnel can be considered competent in terms of knowledge, skill and ability in carrying out occupational safety and health regulation within their respective organization. While, 96.9% of the respondents that participated in the survey can be considered not competent. The authors hope the result of this survey could assist the relevant authorities in formulating a better policy and strategy for implementing occupational safety and health in SMEs involved in chemical industry sub-sectors.
    Matched MeSH terms: Chemical Industry
  6. Vegetative and reproductive growth behaviour of xanthostemon chrysanthus (F. Muell.) benth. – an ornamental tree in Malaysia
    Ahmad Nazarudin M, Tsan F
    Sains Malaysiana, 2018;47:227-233.
    A study was conducted to investigate the duration of growth stages and flowering behaviour of a landscape tree,
    Xanthostemon chrysanthus (F. Muell.) Benth. This species is known as golden penda and locally known as jambu kuning.
    It is widely planted for urban beautification due to its distinctive coloured flowers. Under local climate condition, this
    species flowers throughout the year. However, the flowering of this species has not been studied extensively. In the present
    study, the growth of selected trees aged approximately six years after planting was monitored for a year. The growth
    duration was determined using the extended Biologishe Bundesanstalt, Bundessortenamt and Chemical Industry (BBCH)
    scale. Percentages of flower and fruit and new leaf abundances were expressed as estimated percentage of each stage as
    compared to total surface area of the tree crown. The vegetative and reproductive stages of the species required 198 and
    176 days, respectively. The flowering period took about 40 days from inflorescence bud swelling to drying and senescence
    of stamens and petals. Unsynchronized flowering was observed among the trees. The occurrence of flowers was also
    influenced by the development of new leaves or fruits. The information on the duration of each growth stage and the
    flowering behaviour of the species may enhance a more detailed study related to flowering of urban trees in Malaysia.
    Matched MeSH terms: Chemical Industry
  7. Bio-electrochemical power generation in petrochemical wastewater fed microbial fuel cell
    Sarmin S, Ethiraj B, Islam MA, Ideris A, Yee CS, Khan MMR
    Sci Total Environ, 2019 Dec 10;695:133820.
    PMID: 31416036 DOI: 10.1016/j.scitotenv.2019.133820
    The petrochemical wastewater (PCW) from acrylic acid plants possesses a very high chemical oxygen demand (COD) due to the presence of acrylic acid along with other organic acids. The treatment of PCW by conventional aerobic and anaerobic methods is energy intensive. Therefore, the treatment of PCW with concurrent power generation by employing microbial fuel cell (MFC) could be a potential alternative to solve the energy and environmental issues. This study demonstrates the potentiality of PCW from acrylic acid plant with an initial COD of 45,000 mg L-1 generating maximum power density of 850 mW m-2 at a current density of 1500 mA m-2 using acclimatized anaerobic sludge (AS) as biocatalyst. The predominant microbes present in acclimatized AS were identified using Biolog GEN III analysis, which include the electrogenic genera namely Pseudomonas spp. and Bacillus spp. along with methanogenic archea Methanobacterium spp. The mechanism of electron transfer was elucidated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) which clearly demonstrated the natural metabolite-based electron transfer across the electrode/biofilm/solution interface. The abundance of the electron shuttle metabolites was increased with the microbial growth in the bulk solution as well as in the biofilm leading to a high power generation. The COD removal efficiency and the coulombic efficiency (CE) were found to be 40% and 21%, respectively after 11 days of operation using initial COD of 45,000 mg L-1. The low COD removal efficiency could drastically be increased to 82% when the initial COD of PCW was 5000 mg L-1 generating a power density of 150 mW m-2. The current work proves the feasibility of the MFC for the treatment of acrylic acid plant PCW using acclimatized anaerobic sludge (AS) as a biocatalyst.
    Matched MeSH terms: Chemical Industry
  8. Fulltext Saving primary energy consumption through exergy analysis of combine distillation and power plant
    Alhassan Salami Tijani, Nazri Mohammed, Werner Witt
    Scientific Research Journal, 2012;9(2):0-0.
    MyJurnal
    Industrial heat pumps are heat-recovery systems that allow the temperature of waste-heat stream to be increased to a higher, more efficient temperature. Consequently, heat pumps can improve energy efficiency in industrial processes as well as energy savings when conventional passive-heat recovery is not possible. In this paper, possible ways of saving energy in the chemical industry are considered, the objective is to reduce the primary energy (such as coal) consumption of power plant. Particularly the thermodynamic analyses of integrating backpressure turbine of a power plant with distillation units have been considered. Some practical examples such as conventional distillation unit and heat pump are used as a means of reducing primary energy consumption with tangible indications of energy savings. The heat pump distillation is operated via electrical power from the power plant. The exergy efficiency of the primary fuel is calculated for different operating range of the heat pump distillation. This is then compared with a conventional distillation unit that depends on saturated steam from a power plant as the source of energy. The results obtained show that heat pump distillation is an economic way to save energy if the temperature difference between the overhead and the bottom is small. Based on the result, the energy saved by the application of a heat pump distillation is improved compared to conventional distillation unit.
    Matched MeSH terms: Chemical Industry
  9. Emergency response programme in a petrochemical company in Malaysia
    Jefferelli Shamsul Bahrin, Mohamad Husain Sajahan, Mohd. Nazri Hamad
    Journal of Occupational Safety and Health, 2004;1(1):3-8.
    MyJurnal
    Malaysia is blessed with oil and gas resources, which form raw materials for the petrochemical industry. The petrochemical industry creates added value to this resource and is an important contributor to the national economy. The petrochemical industry however also creates hazards of which fire or explosions and chemical release are of special concern. These hazards pose a risk not only to workers but also to the surrounding population and environment. To ensure industry is prepared to cope with emergencies, a comprehensive emergency response programme is necessary. This is inline with both the Malaysian Occupational Safety and Health (Control of Industrial Major Accident Hazards) Regulations 1996 and the Responsible Care initiative of the chemical industry. This paper describes elements to be considered in an emergency response programme for industry such as the concept of emergency management, organisation, duties and responsibilities, emergency system, training and mutual aid plans and agreements. We shall provide related examples based on a multinational petrochemical company practice.
    Matched MeSH terms: Chemical Industry
  10. Determination of optimum harvest maturity and non-destructive evaluation of pod development and maturity in cacao (Theobroma cacao L.) using a multiparametric fluorescence sensor
    Tee YK, Balasundram SK, Ding P, M Hanif AH, Bariah K
    J Sci Food Agric, 2019 Mar 15;99(4):1700-1708.
    PMID: 30206959 DOI: 10.1002/jsfa.9359
    BACKGROUND: A series of fluorescence indices (anthocyanin, flavonol, chlorophyll and nitrogen balance) were deployed to detect the pigments and colourless flavonoids in cacao pods of three commercial cacao (Theobroma cacao L.) genotypes (QH1003, KKM22 and MCBC1) using a fast and non-destructive multiparametric fluorescence sensor. The aim was to determine optimum harvest periods (either 4 or 5 months after pod emergence) of commercial cacao based on fluorescence indices of cacao development and bean quality.

    RESULTS: As pod developed, cacao exhibited a rise with the peak of flavonol occurring at months 4 and 5 after pod maturity was initiated while nitrogen balance showed a decreasing trend during maturity. Cacao pods contained high chlorophyll as they developed but chlorophyll content declined significantly on pods that ripened at month 5.

    CONCLUSION: Cacao pods harvested at months 4 and 5 can be considered as commercially-ready as the beans have developed good quality and comply with the Malaysian standard on cacao bean specification. Thus, cacao pods can be harvested earlier when they reach maturity at month 4 after pod emergence to avoid germinated beans and over fermentation in ripe pods harvested at month 5. © 2018 Society of Chemical Industry.

    Matched MeSH terms: Chemical Industry
  11. Fulltext Adoption of responsible care program in Malaysian chemical industries: current status and way forward
    NurKhairlida Muhamad Khai, Khai EL, Mazlin Mokhta, Choo TG, Marlia Mohd Hanafiah, Chan PW, et al.
    Malaysian Journal of Public Health Medicine, 2017;17 Special(1):1-6.
    Chemical industry is one of the important industries in the world. However, incidents happened due to the release of hazardous materials, toxic and poisonous chemicals in the chemical industries can cause fatal to human and destruction of the environment. Learning from the Bhopal disaster's experience, chemical industries have developed a program - Responsible Care, aiming to regain public trust through improving the environment, health and safety performances. Malaysia has adopted Responsible Care program since 1994 under the stewardship of the Chemical Industries Council of Malaysia (CICM). Six codes of management practices have been developed by the CICM, covering distribution, community awareness and emergency response, pollution prevention, process safety, employee health & safety and product stewardship. It has been more than 20 years since its inception. However, to date, there are only 125 companies have signed the pledge to adopt Responsible Care program. The CICM has also conducted several initiatives to encourage participation of chemical companies to adopt Responsible Care program in Malaysia. Therefore, it is the aim of this paper to review the current status of Responsible Care program in Malaysia and also deliberate the way forward of this program.
    Matched MeSH terms: Chemical Industry
  12. Fault diagnosis of the polypropylene production process (UNIPOL PP) using ANFIS
    Lau CK, Heng YS, Hussain MA, Mohamad Nor MI
    ISA Trans, 2010 Oct;49(4):559-66.
    PMID: 20667537 DOI: 10.1016/j.isatra.2010.06.007
    The performance of a chemical process plant can gradually degrade due to deterioration of the process equipment and unpermitted deviation of the characteristic variables of the system. Hence, advanced supervision is required for early detection, isolation and correction of abnormal conditions. This work presents the use of an adaptive neuro-fuzzy inference system (ANFIS) for online fault diagnosis of a gas-phase polypropylene production process with emphasis on fast and accurate diagnosis, multiple fault identification and adaptability. The most influential inputs are selected from the raw measured data sets and fed to multiple ANFIS classifiers to identify faults occurring in the process, eliminating the requirement of a detailed process model. Simulation results illustrated that the proposed method effectively diagnosed different fault types and severities, and that it has a better performance compared to a conventional multivariate statistical approach based on principal component analysis (PCA). The proposed method is shown to be simple to apply, robust to measurement noise and able to rapidly discriminate between multiple faults occurring simultaneously. This method is applicable for plant-wide monitoring and can serve as an early warning system to identify process upsets that could threaten the process operation ahead of time.
    Matched MeSH terms: Chemical Industry/statistics & numerical data*
  13. The effects of perceived organizational support, perceived supervisor support and perceived co-worker support on safety and health compliance
    Puah LN, Ong LD, Chong WY
    Int J Occup Saf Ergon, 2016 Sep;22(3):333-9.
    PMID: 27049935 DOI: 10.1080/10803548.2016.1159390
    Although knowledge is cumulating, very little is known about the effects of various sources of support on safety and health compliance. This study goes beyond previous research by investigating the relationships among perceived support from organizations, supervisors and co-workers, and employees' safety and health compliance behaviour at chemical and petroleum process plants. The results of this study show that the support from organizations, supervisors and co-workers was significantly related to employees' safety and health compliance. Also, the findings reveal that perceived supervisor support has the strongest influence in ensuring employees' safety and health compliance behaviour.
    Matched MeSH terms: Chemical Industry/organization & administration
  14. Connotations of psychological and physiological health in the psychosocial work environment: An industrial context
    Javaid MU, Bano S, Mirza MZ, Isha ASN, Nadeem S, Jawaid A, et al.
    Work, 2019;64(3):551-561.
    PMID: 31658088 DOI: 10.3233/WOR-193016
    BACKGROUND: Psychological conditions are experiences of the conscious and unconscious elements of the work context, which revolve around workers' perceptions of feeling either engaged or disengaged with the assigned tasks. In the psychosocial work environment of hazardous industries like petrochemicals where production lasts twenty-four hours a day and continues seven-days-a-week, a psychologically available worker is extremely important. Psychological availability refers to when workers who are physically, emotionally and psychologically engaged at the moment of performing tasks.

    OBJECTIVE: The broad objective of this study was to investigate the direct and indirect effects of behavioral factors on the psychological and physiological health of workers.

    METHODS: The latest, second generation technique, which is structural equation modeling, is used to identify the relationships between behavioral antecedents and health outcomes. A total of 277 technical workers participated, aged between 20 and 49 and were healthy in all aspects.

    RESULTS: The study results showed quantitative demands, emotional demands, work-family conflict, and job insecurity were significantly associated with both psychological (stress) and physiological (Body Mass Index) factors. The social support of colleagues produced mixed findings with direct and indirect paths. Stress also significantly mediates the psychosocial factors and burnout of the workers.

    CONCLUSION: The study concluded that workers were physically available, but they experienced distractions as members of social systems, affecting their physiological and psychological health.

    Matched MeSH terms: Chemical Industry*
  15. Impact of biochar and compost amendment on soil quality, growth and yield of a replanted apple orchard in a 4-year field study
    Safaei Khorram M, Zhang G, Fatemi A, Kiefer R, Maddah K, Baqar M, et al.
    J Sci Food Agric, 2019 Mar 15;99(4):1862-1869.
    PMID: 30264414 DOI: 10.1002/jsfa.9380
    BACKGROUND: Numerous studies have addressed the positive effects of organic amendments on soil and plant productivity under short-term field studies. However, to date, few studies have been conducted on the effects of organic amendment on the orchards where high nutrient bioavailability is required. This study deals with the effects of biochar and compost on soil quality, growth and yield of a replanted apple orchard in the northeast of Iran.

    RESULTS: Biochar+compost application resulted in 37% and 300% higher soil total organic carbon and available phosphorus content, respectively, during the first 3 years of experimentation compared to control. Similarly, trunk diameter and shoot number of apple trees increased 23-26% by the end of the first year. Nevertheless, there were no significant changes in fruitfulness, fruit weight or starch pattern index as productivity indices.

    CONCLUSION: Biochar and compost were beneficial in improving soil quality, mainly by increasing soil nutrient content and decreasing soil bulk density, and in increasing plant growth at early growth stages of apple orchards. However, they failed to enhance overall yield and fruit quality, most likely due to their limited ability to suppress apple replant disease. © 2018 Society of Chemical Industry.

    Matched MeSH terms: Chemical Industry
  16. A clinical survey of paraquat formulation workers
    Howard JK
    Br J Ind Med, 1979 Aug;36(3):220-3.
    PMID: 500781
    A group of 18 male Caucasian workers from the United Kingdom and a further group of 18 male mixed race (mainly Malay) workers from Malaysia employed in the formulation of paraquat-based herbicides were examined for evidence of chronic ill health after long-term exposure to paraquat. Clinical records were examined, medical and occupational histories were obtained and a clinical examination, particularly of the skin, was undertaken. Skin rashes, nail damage and epistaxes were encountered by most workers as a result of direct contact of skin and mucous membranes with paraquat. These conditions subsided rapidly and no worker reported any sequelae. There was no clinical evidence of long-term effects on skin, mucous membranes or general health following exposure to paraquat over several years in these workers.
    Matched MeSH terms: Chemical Industry*
  17. Evaluation of radiological risks due to natural radioactivity around Lynas Advanced Material Plant environment, Kuantan, Pahang, Malaysia
    Kolo MT, Aziz SA, Khandaker MU, Asaduzzaman K, Amin YM
    Environ Sci Pollut Res Int, 2015 Sep;22(17):13127-36.
    PMID: 25925148 DOI: 10.1007/s11356-015-4577-5
    Understanding the public awareness concerning the Lynas Advanced Material Plant (LAMP), an Australian rare earths processing plant located in Malaysia, a radiological study in soil and water samples collected at random surrounding the LAMP environment was undertaken using HPGe gamma-ray spectrometry. The mean soil activities for (226)Ra, (232)Th, and (40)K were found to be 6.56 ± 0.20, 10.62 ± 0.42, and 41.02 ± 0.67 Bq/kg, respectively, while for water samples were 0.33 ± 0.05, 0.18 ± 0.04, and 4.72 ± 0.29 Bq/l, respectively. The studied areas show typical local level of radioactivity from natural background radiation. The mean gamma absorbed dose rate in soils at 1 m above the ground was found to be 11.16 nGy/h. Assuming a 20 % outdoor occupancy factor, the corresponding annual effective dose showed a mean value of 0.014 mSv year(-1), significantly lower than the worldwide average value of 0.07 mSv year(-1) for the annual outdoor effective dose as reported by UNSCEAR (2000). Some other representative radiation indices such as activity utilization index (AUI), H ex, H in, excess lifetime cancer risk (ELCR), and annual gonadal dose equivalent (AGDE) were derived and also compared with the world average values. Statistical analysis performed on the obtained data showed a strong positive correlation between the radiological variables and (226)Ra and (232)Th.
    Matched MeSH terms: Chemical Industry
  18. Analysis of the comprehensibility of chemical hazard communication tools at the industrial workplace
    Ta GC, Mokhtar MB, Mohd Mokhtar HA, Ismail AB, Abu Yazid MF
    Ind Health, 2010;48(6):835-44.
    PMID: 20616463
    Chemical classification and labelling systems may be roughly similar from one country to another but there are significant differences too. In order to harmonize various chemical classification systems and ultimately provide consistent chemical hazard communication tools worldwide, the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) was endorsed by the United Nations Economic and Social Council (ECOSOC). Several countries, including Japan, Taiwan, Korea and Malaysia, are now in the process of implementing GHS. It is essential to ascertain the comprehensibility of chemical hazard communication tools that are described in the GHS documents, namely the chemical labels and Safety Data Sheets (SDS). Comprehensibility Testing (CT) was carried out with a mixed group of industrial workers in Malaysia (n=150) and factors that influence the comprehensibility were analysed using one-way ANOVA. The ability of the respondents to retrieve information from the SDS was also tested in this study. The findings show that almost all the GHS pictograms meet the ISO comprehension criteria and it is concluded that the underlying core elements that enhance comprehension of GHS pictograms and which are also essential in developing competent persons in the use of SDS are training and education.
    Matched MeSH terms: Chemical Industry/statistics & numerical data*
  19. Fulltext Dehalogenases: From Improved Performance to Potential Microbial Dehalogenation Applications
    Ang TF, Maiangwa J, Salleh AB, Normi YM, Leow TC
    Molecules, 2018 05 07;23(5).
    PMID: 29735886 DOI: 10.3390/molecules23051100
    The variety of halogenated substances and their derivatives widely used as pesticides, herbicides and other industrial products is of great concern due to the hazardous nature of these compounds owing to their toxicity, and persistent environmental pollution. Therefore, from the viewpoint of environmental technology, the need for environmentally relevant enzymes involved in biodegradation of these pollutants has received a great boost. One result of this great deal of attention has been the identification of environmentally relevant bacteria that produce hydrolytic dehalogenases—key enzymes which are considered cost-effective and eco-friendly in the removal and detoxification of these pollutants. These group of enzymes catalyzing the cleavage of the carbon-halogen bond of organohalogen compounds have potential applications in the chemical industry and bioremediation. The dehalogenases make use of fundamentally different strategies with a common mechanism to cleave carbon-halogen bonds whereby, an active-site carboxylate group attacks the substrate C atom bound to the halogen atom to form an ester intermediate and a halide ion with subsequent hydrolysis of the intermediate. Structurally, these dehalogenases have been characterized and shown to use substitution mechanisms that proceed via a covalent aspartyl intermediate. More so, the widest dehalogenation spectrum of electron acceptors tested with bacterial strains which could dehalogenate recalcitrant organohalides has further proven the versatility of bacterial dehalogenators to be considered when determining the fate of halogenated organics at contaminated sites. In this review, the general features of most widely studied bacterial dehalogenases, their structural properties, basis of the degradation of organohalides and their derivatives and how they have been improved for various applications is discussed.
    Matched MeSH terms: Chemical Industry
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