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Fulltext Prevalence of the metabolic syndrome and its influencing factors among adolescent girls in Mashhad, Iran

Mirhosseini NZ, Yusoff NA, Shahar S, Parizadeh SM, Mobarhen MG, Shakery MT

Asia Pac J Clin Nutr, 2009;18(1):131-6.
PMID: 19329406

Introduction: This study sought to determine the prevalence of the metabolic syndrome, one of the major public-health challenges worldwide, and its influencing factors among 15 to 17 years old adolescent girls in Mashhad, Iran.
Methods: A total of 622 high school adolescents participated in a cross-sectional study. A self-administered questionnaire was used to assess socio-demographic characteristics and dietary habits. Anthropometric assessments, blood pressure measurement and biochemical assessment were done.
Results: Applying BMI Z-score for age and gender (WHO 2007), 14.6 % and 3.4 % of subjects were classified as overweight and obese, respectively. Enlarged WC (> 80 cm) was seen in 9.5% of subjects. The prevalence of combined hypertension was 6.1% which was increased by the severity of obesity. A total of 24.5% of subjects had hypertriglyceridemia and 57% of them had low level of HDL-cholesterol. Hyperglycemia was present in 16.7% of subjects. Based on the NCEP ATP III (2001) criteria, the prevalence of the metabolic syndrome was 6.5% and increased to 45.1% in obese subjects. Increasing BMI or WC, led to significant increment in the number of metabolic syndrome features (p < 0.001). High socioeconomic status of family, medical history of parents and dietary habits especially high consumption of carbohydrates were influencing factors in the prevalence of the metabolic syndrome.
Conclusion: Approximately 6.5% of all and 45% of obese subjects met the criteria for the metabolic syndrome. Dietary habits especially carbohydrate consumption, socioeconomic status of family and medical history of parents can be influential factors in the prevalence of the metabolic syndrome.
Mutagenesis of the nucleocapsid protein of Nipah virus involved in capsid assembly

Ong ST, Yusoff K, Kho CL, Abdullah JO, Tan WS

J Gen Virol, 2009 Feb;90(Pt 2):392-397.
PMID: 19141448 DOI: 10.1099/vir.0.005710-0

The nucleocapsid protein of Nipah virus produced in Escherichia coli assembled into herringbone-like particles. The amino- and carboxy-termini of the N protein were shortened progressively to define the minimum contiguous sequence involved in capsid assembly. The first 29 aa residues of the N protein are dispensable for capsid formation. The 128 carboxy-terminal residues do not play a role in the assembly of the herringbone-like particles. A region with amino acid residues 30-32 plays a crucial role in the formation of the capsid particle. Deletion of any of the four conserved hydrophobic regions in the N protein impaired capsid formation. Replacement of the central conserved regions with the respective sequences from the Newcastle disease virus restored capsid formation.
Diacylglycerol and triacylglycerol as responses in a dual response surface-optimized process for diacylglycerol production by lipase-catalyzed esterification in a pilot packed-bed enzyme reactor

Lo SK, Cheong LZ, Arifin N, Tan CP, Long K, Yusoff MS, et al.

J Agric Food Chem, 2007 Jul 11;55(14):5595-603.
PMID: 17571899

Diacylglycerol (DAG) and triacylglycerol (TAG) as responses on optimization of DAG production using a dual response approach of response surface methodology were investigated. This approach takes the molecular equilibrium of DAG into account and allows for the optimization of reaction conditions to achieve maximum DAG and minimum TAG yields. The esterification reaction was optimized with four factors using a central composite rotatable design. The following optimized conditions yielded 48 wt % DAG and 14 wt % TAG: reaction temperature of 66.29 degrees C, enzyme dosage of 4 wt %, fatty acid/glycerol molar ratio of 2.14, and reaction time of 4.14 h. Similar results were achieved when the process was scaled up to a 10 kg production in a pilot packed-bed enzyme reactor. Lipozyme RM IM did not show any significant activity losses or changes in fatty acid selectivity on DAG synthesis during the 10 pilot productions. However, lipozyme RM IM displayed higher selectivity toward the production of oleic acid-enriched DAG. The purity of DAG oil after purification was 92 wt %.
Nutrient removal in a pilot and full scale constructed wetland, Putrajaya city, Malaysia

Sim CH, Yusoff MK, Shutes B, Ho SC, Mansor M

J Environ Manage, 2008 Jul;88(2):307-17.
PMID: 17467147

Putrajaya Wetlands in Malaysia, a 200ha constructed wetland system consisting of 24 cells, was created in 1997-1998 to treat surface runoff caused by development and agricultural activities from an upstream catchment before entering Putrajaya Lake (400ha). It was designed for stormwater treatment, flood control and amenity use. The water quality improvement performance of a section of the wetland cells is described. The nutrient removal performance was 82.11% for total nitrogen, 70.73% for nitrate-nitrogen and 84.32% for phosphate, respectively, along six wetland cells from Upper North UN6 to UN1 from April to December 2004. Nutrient removal in pilot scale tank systems, simulating a constructed wetland and planted with examples of common species at Putrajaya, the Common Reed Phragmites karka and Tube Sedge Lepironia articulata, and the capacity of these species to retain nutrients in above and below-ground plant biomass and substrate is reported. The uptake of nutrients by the Common Reed and Tube Sedge from the pilot tank system was 42.1% TKN; 28.9% P and 17.4% TKN; 26.1% P, respectively. The nutrient uptake efficiency of the Common Reed was higher in above-ground than in below-ground tissue. The results have implications for plant species selection in the design of constructed wetlands in Malaysia and for optimizing the performance of these systems.
Structural analysis of peptides that interact with Newcastle disease virus

Chia SL, Tan WS, Shaari K, Abdul Rahman N, Yusoff K, Satyanarayanajois SD

Peptides, 2006 Jun;27(6):1217-25.
PMID: 16377031

A peptide with the sequence CTLTTKLYC has previously been identified to inhibit the propagation of Newcastle disease virus (NDV) in embryonated chicken eggs and tissue culture. NDV has been classified into two main groups: the velogenic group, and mesogenic with lentogenic strains as the other group based on its dissociation constants. In this study the peptide, CTLTTKLYC, displayed on the pIII protein of a filamentous M13 phage was synthesized and mutated in order to identify the amino acid residues involved in the interactions with NDV. Mutations of C1 and K6 to A1 and A6 did not affect the binding significantly, but substitution of Y8 with A8 dramatically reduced the interaction. This suggests that Y8 plays an important role in the peptide-virus interaction. The three-dimensional structure of the peptide was determined using circular dichroism (CD), nuclear magnetic resonance (NMR), and molecular modeling. The peptide exhibited two possible conformers. One that consists of consecutive beta-turns around T2-L3-T4-T5 and K6-L7-Y8-C9. The other conformer exhibited a beta-hairpin bend type of structure with a bend around L3-T4-T5-K6.
Fulltext Molecular genetic analysis of a supratentorial haemangioblastoma in a non-Von Hippel Lindau patient

Zamzuri I, Ghazali MM, Zainuddin N, Sulong S, Samarendra SM, Yusoff AAM, et al.

Med J Malaysia, 2005 Aug;60(3):360-3.
PMID: 16379193

We describe a rare tumor site in a 46 year old man who presented with a two week history of headache. Physical examination revealed bilateral papilloedema with no other localizing signs. Computed Tomographic Scan as well as Magnetic Resonance Imaging of the brain revealed a lesion with a dura tail located adjacent to the falx cerebri of the right frontal lobe. This lesion was not invading the inner table of the skull base. A tumor blush was seen on angiogram. There were no abnormalities on CT scan of the abdomen and fundoscopy was normal. Intraoperatively a vascular tumor not attached to the dura was noted and removed totally. Histopathological examination was typical of a hemangioblastoma. Analysis revealed no mutations of the VHL gene in 5 regions, exon 5-8 of the p53 gene, exon 1-2 of the p16 gene and exon 5,6 and 8 of the PTEN gene. This is the first case report of a supratentorial hemangioblastoma in a non-Von Hippel Lindau patient with genetic evidence.
Gender differences in coping skills of parents with hearing-impaired children

Md Daud MK, Noor SS, Yusoff MN, Abd Rahman N, Zakaria MN

B-ENT, 2013;9(4):319-23.
PMID: 24597108

To assess differences between the coping strategies of the mothers and fathers with hearing-impaired children.
Impact of chemotherapy on hypercalcemia in breast and lung cancer patients

Hassan BA, Yusoff ZB, Hassali MA, Othman SB, Weiderpass E

Asian Pac J Cancer Prev, 2012;13(9):4373-8.
PMID: 23167346

INTRODUCTION: Hypercalcemia is mainly caused by bone resorption due to either secretion of cytokines including parathyroid hormone-related protein (PTHrP) or bone metastases. However, hypercalcemia may occur in patients with or without bone metastases. The present study aimed to describe the effect of chemotherapy treatment, regimens and doses on calcium levels among breast and lung cancer patients with hypercalcemia.
METHODS: We carried a review of medical records of breast and lung cancer patients hospitalized in years 2003 and 2009 at Penang General Hospital, a public tertiary care center in Penang Island, north of Malaysia. Patients with hypercalcemia (defined as a calcium level above 10.5 mg/dl) at the time of cancer diagnosis or during cancer treatment had their medical history abstracted, including presence of metastasis, chemotherapy types and doses, calcium levels throughout cancer treatment, and other co-morbidity. The mean calcium levels at first hospitalization before chemotherapy were compared with calcium levels at the end of or at the latest chemotherapy treatment. Statistical analysis was conducted using the Chi-square test for categorical data, logistic regression test for categorical variables, and Spearman correlation test, linear regression and the paired sample t tests for continuous data.
RESULTS: Of a total 1,023 of breast cancer and 814 lung cancer patients identified, 292 had hypercalcemia at first hospitalization or during cancer treatment (174 breast and 118 lung cancer patients). About a quarter of these patients had advanced stage cancers: 26.4% had mild hypercalcemia (10.5-11.9 mg/dl), 55.5% had moderate (12-12.9 mg/dl), and 18.2% severe hypercalcemia (13-13.9; 14-16 mg/dl). Chemotherapy lowered calcium levels significantly both in breast and lung cancer patients with hypercalcemia; in particular with chemotherapy type 5-flurouracil+epirubicin+cyclophosphamide (FEC) for breast cancer, and gemcitabine+cisplatin in lung cancer.
CONCLUSION: Chemotherapy decreases calcium levels in breast and lung cancer cases with hypercalcemia at cancer diagnosis, probably by reducing PTHrP levels.
Comparison of the patterns of antral follicular development between hormonally synchronized and natural estrous cycles of non-seasonal, polyestrous goats in the tropics

Bukar MM, Yusoff R, Ariff OM, Haron AW, Dhaliwal GK, Naing SW, et al.

Reprod Biol, 2012 Nov;12(3):325-8.
PMID: 23153704 DOI: 10.1016/j.repbio.2012.09.004

The effects of estrus synchronization with prostaglandin F(2α) (PGF(2α)) and Controlled Internal Drug Release Device (CIDR) on ensuing antral follicular development were documented and compared to natural estrous cycles of non-seasonal tropical goats. Two to six follicular waves were observed, with the three-follicular wave pattern being most frequently observed (58%), followed by four follicular waves (31.6%) per estrous cycle. There were no significant differences (p>0.05) between the PGF(2α)- or CIDR-synchronized and natural estrous cycles nor between the synchronized and subsequent non-synchronized cycles in terms of the time of ovulation, the duration of inter-ovulatory intervals, daily numbers of antral follicles ≥3mm in diameter, and the number of follicular waves per cycle in the goats of the present study.
Fulltext 1-[4-(Prop-2-en-1-yl-oxy)benz-yl]-2-[4-(prop-2-en-1-yl-oxy)phen-yl]-1H-benzimidazole

Rahman ML, Kwong HC, Mohd Yusoff M, Hegde G, Mohamed Tahir MI

Acta Crystallogr Sect E Struct Rep Online, 2012 Dec 1;68(Pt 12):o3311-2.
PMID: 23476157 DOI: 10.1107/S160053681204559X

In the title compound, C26H24N2O2, the benzimidazole ring system is almost planar [maximum displacement = 0.025 (1) Å] and makes dihedral angles of 80.48 (5) and 41.57 (5)° with the benzene rings, which are inclined to one another by 65.33 (6)°. In the crystal, mol-ecules are linked via C-H⋯π and weak π-π inter-actions [centroid-centroid distance = 3.8070 (7) Å and inter-planar distance = 3.6160 (5) Å].
Fulltext Real space flight travel is associated with ultrastructural changes, cytoskeletal disruption and premature senescence of HUVEC

Kapitonova MY, Muid S, Froemming GR, Yusoff WN, Othman S, Ali AM, et al.

Malays J Pathol, 2012 Dec;34(2):103-13.
PMID: 23424772 MyJurnal

Microgravity, hypergravity, vibration, ionizing radiation and temperature fluctuations are major factors of outer space flight affecting human organs and tissues. There are several reports on the effect of space flight on different human cell types of mesenchymal origin while information regarding changes to vascular endothelial cells is scarce. Ultrastructural and cytophysiological features of macrovascular endothelial cells in outer space flight and their persistence during subsequent culturing were demonstrated in the present investigation. At the end of the space flight, endothelial cells displayed profound changes indicating cytoskeletal lesions and increased cell membrane permeability. Readapted cells of subsequent passages exhibited persisting cytoskeletal changes, decreased metabolism and cell growth indicating cellular senescence.
Fulltext Structural and optical properties of lead-boro-tellurrite glasses induced by gamma-ray

Mustafa IS, Kamari HM, Yusoff WM, Aziz SA, Rahman AA

Int J Mol Sci, 2013;14(2):3201-14.
PMID: 23380963 DOI: 10.3390/ijms14023201

Spectrophotometric studies of lead borotellurite glasses were carried out before and after gamma irradiation exposure. The increasing peak on the TeO(4) bi-pyramidal arrangement and TeO(3+1) (or distorted TeO(4)) is due to augmentation of irradiation dose which is attributed to an increase in degree of disorder of the amorphous phase. The structures of lead tellurate contain Pb(3)TeO(6) consisting of TeO(3) trigonal pyramid connected by PbO(4) tetragonal forming a three-dimensional network. The decrease of glass rigidity is due to irradiation process which is supported by the XRD diffractograms results. The decreasing values of absorption edge indicate that red shift effect occur after irradiation processes. A shift in the optical absorption edge attributed to an increase of the conjugation length. The values of optical band gap, E(opt) were calculated and found to be dependent on the glass composition and radiation exposure. Generally, an increase and decrease in Urbach's energy can be considered as being due to an increase in defects within glass network.
Fulltext Methodology of Global Adult Tobacco Survey (GATS), Malaysia, 2011

Omar A, Yusoff MF, Hiong TG, Aris T, Morton J, Pujari S

Int J Public Health Res, 2013;3(2):297-305.
PMID: 26451348 MyJurnal

INTRODUCTION: Malaysia participated in the second phase of the Global Adult Tobacco Survey (GATS) in 2011. GATS, a new component of the Global Tobacco Surveillance System, is a nationally representative household survey of adults 15 years old or above. The objectives of GATS Malaysia were to (i) systematically monitor tobacco use among adults and track key indicators of tobacco control and (ii) track the implementation of some of the Framework Convention of Tobacco Control (FCTC)-recommended demand related policies.
METHODS: GATS Malaysia 2011 was a nationwide cross-sectional survey using multistage stratified sampling to select 5112 nationally representative households. One individual aged 15 years or older was randomly chosen from each selected household and interviewed using handheld device. GATS Core Questionnaire with optional questions was pre-tested and uploaded into handheld devices after repeated quality control processes. Data collectors were trained through a centralized training. Manuals and picture book were prepared to aid in the training of data collectors and during data collection. Field-level data were aggregated on a daily basis and analysed twice a week. Quality controls were instituted to ensure collection of high quality data. Sample weighting and analysis were conducted with the assistance of researchers from the Centers for Disease Control and Prevention, Atlanta, USA.
RESULTS: GATS Malaysia received a total response rate of 85.3% from 5112 adults surveyed. Majority of the respondents were 25-44 years old and Malays.
CONCLUSIONS: The robust methodology used in the GATS Malaysia provides national estimates for tobacco used classified by socio-demographic characteristics and reliable data on various dimensions of tobacco control.
Study name: Global Adults Tobacco Survey (GATS-2011)
Fulltext Prevalence and associated factors of stress, anxiety and depression among prospective medical students

Yusoff MS, Abdul Rahim AF, Baba AA, Ismail SB, Mat Pa MN, Esa AR

Asian J Psychiatr, 2013 Apr;6(2):128-33.
PMID: 23466109 DOI: 10.1016/j.ajp.2012.09.012

Many studies have reported that the prevalence of psychological distress among medical students during medical training was high. However, there are very few studies exploring on the psychological health of prospective medical students. This study aimed to determine the prevalence and associated factors for stress, anxiety and depression symptoms among the prospective medical students. A cross-sectional study was done on two cohorts of applicants to a public medical school. A total of 839 applicants were invited to participate in the study. The 21-item Depression Anxiety Stress Scale was administered to the applicants after they completed interviews. A total of 743 (92.2%) applicants took part in the study. The prevalence of moderate to extremely severe level of stress, anxiety and depression were 3.6%, 54.5% and 1.9%, respectively. Stress was significantly associated with extra-curricular activity (p<0.001) and race (p<0.001). Anxiety was associated with extra-curricular activity (p<0.001), race (p<0.001), mother education level (p=0.002) and CGPA group (p=0.034). Depression was associated with academic performance in class (p<0.001) and race (p=0.004). Prevalence of stress and depression among entering medical students was low; however prevalence of anxiety was high which could be due to worry about the interviews to enter medical course. The associated factors of psychological distress among prospective medical students were related to academic, non-academic, parent education and cultural backgrounds.
Comparative evaluation of three purification methods for the nucleocapsid protein of Newcastle disease virus from Escherichia coli homogenates

Tan YP, Ling TC, Yusoff K, Tan WS, Tey BT

J Microbiol, 2005 Jun;43(3):295-300.
PMID: 15995649

In the present study, the performances of conventional purification methods, packed bed adsorption (PBA), and expanded bed adsorption (EBA) for the purification of the nucleocapsid protein (NP) of Newcastle disease virus (NDV) from Escherichia coli homogenates were evaluated. The conventional methods for the recovery of NP proteins involved multiple steps, such as centrifugation, precipitation, dialysis, and sucrose gradient ultracentrifugation. For the PBA, clarified feedstock was used for column loading, while in EBA, unclarified feedstock was used. Streamline chelating immobilized with Ni2+ ion was used as an affinity ligand for both PBA and EBA. The final protein yield obtained in conventional and PBA methods was 1.26% and 5.56%, respectively. It was demonstrated that EBA achieved the highest final protein yield of 9.6% with a purification factor of 7. Additionally, the total processing time of the EBA process has been shortened by 8 times compared to that of the conventional method.
Fulltext G6PD Viangchan and G6PD Mediterranean are the main variants in G6PD deficiency in the Malay population of Malaysia

Mohd Yusoff N, Shirakawa T, Nishiyama K, Choo KE, Isa MN, Matsuo M

Southeast Asian J. Trop. Med. Public Health, 2003;34 Suppl 3:135-7.
PMID: 15906717

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked red blood cell enzymopathy common in malaria endemic areas. Individuals affected by this disease show a wide variety of clinical signs of acute hemolytic anemia. Mutations of the G6PD gene in the Malay population with G6PD deficiency in Kelantan, a state in North East Malaysia were studied. Ninety-three individuals with G6PD deficiency were subjected to mutation analysis of the G6PD gene using polymerase chain reaction based techniques of multiplex PCR. Of the ninety-three DNA samples studied, molecular defects were identified in 80 cases (86%). Variants were heterogeneous - 28.7% were found to have a G to A nucleotide change at nucleotide 871 of the G6PD gene (G871A), corresponding to G6PD Viangchan. The other major mutations were G6PD Mediterranean, G6PD Vanua Lava, G6PD Coimbra, G6PD Kaiping, G6PD Orissa, G6PD Mahidol, G6PD Canton and G6PD Chatham. These results showed that there are heterogeneous mutations of the G6PD gene associated with G6PD deficiency and that G6PD Viangchan and G6PD Mediterranean account for the main variants in G6PD deficiency among the Malay population in Malaysia.
Immobilisation of Cu, Pb and Zn in Scrap Metal Yard Soil Using Selected Waste Materials

Kamari A, Putra WP, Yusoff SN, Ishak CF, Hashim N, Mohamed A, et al.

Bull Environ Contam Toxicol, 2015 Dec;95(6):790-5.
PMID: 26395356 DOI: 10.1007/s00128-015-1650-1

Immobilisation of heavy metals in a 30-year old active scrap metal yard soil using three waste materials, namely coconut tree sawdust (CTS), sugarcane bagasse (SB) and eggshell (ES) was investigated. The contaminated soil was amended with amendments at application rates of 0 %, 1 % and 3 % (w/w). The effects of amendments on metal accumulation in water spinach (Ipomoea aquatica) and soil metal bioavailability were studied in a pot experiment. All amendments increased biomass yield and reduced metal accumulation in the plant shoots. The bioconcentration factor and translocation factor values of the metals were in the order of Zn > Cu > Pb. The addition of ES, an alternative source of calcium carbonate (CaCO3), has significantly increased soil pH and resulted in marked reduction in soil metal bioavailability. Therefore, CTS, SB and ES are promising low-cost immobilising agents to restore metal contaminated land.
Increased Expression of Phosphatidylinositol 3-Kinase p110α and Gene Amplification of PIK3CA in Nasopharyngeal Carcinoma

Yip WK, He PY, Abdullah MA, Yusoff S, Seow HF

Pathol Oncol Res, 2016 Apr;22(2):413-9.
PMID: 26581613 DOI: 10.1007/s12253-015-0007-8

Molecular alterations in PIK3CA oncogene that encodes the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K p110α) are commonly found in human cancers. In this study, we examined the expression of PI3K p110α and PIK3CA gene amplification in 74 nasopharyngeal carcinoma (NPC) cases. Immunohistochemical staining demonstrated overexpression of PI3K p110α protein in 44.6% (33/74) of NPCs and 4.8% (2/42) of the adjacent normal nasopharyngeal mucosa. Copy number of PIK3CA gene was successfully analyzed in 51 of the total NPC cases and 19 non-malignant nasopharynx tissues by quantitative real-time PCR. Using mean + 2(standard deviation) of copy numbers in the non-malignant nasopharynx tissues as a cutoff value, PIK3CA copy number gain was found in 10 of 51 (19.6%) NPC cases. High PI3K p110α expression level was correlated with increased PIK3CA copy number (Spearman's rho =0.324, P = 0.02). PI3K p110α expression and PIK3CA copy number did not associate with Akt phosphorylation, and patient and tumor variables. This study suggests that PI3K p110α overexpression, which is attributed, at least in part, to PIK3CA gene amplification, may contribute to NPC pathogenesis. However, these molecular aberrations may not be responsible for activation of Akt signaling in NPC.
Fulltext Monte Carlo dose calculation in dental amalgam phantom

Aziz MZ, Yusoff AL, Osman ND, Abdullah R, Rabaie NA, Salikin MS

J Med Phys, 2015 Jul-Sep;40(3):150-5.
PMID: 26500401 DOI: 10.4103/0971-6203.165080

It has become a great challenge in the modern radiation treatment to ensure the accuracy of treatment delivery in electron beam therapy. Tissue inhomogeneity has become one of the factors for accurate dose calculation, and this requires complex algorithm calculation like Monte Carlo (MC). On the other hand, computed tomography (CT) images used in treatment planning system need to be trustful as they are the input in radiotherapy treatment. However, with the presence of metal amalgam in treatment volume, the CT images input showed prominent streak artefact, thus, contributed sources of error. Hence, metal amalgam phantom often creates streak artifacts, which cause an error in the dose calculation. Thus, a streak artifact reduction technique was applied to correct the images, and as a result, better images were observed in terms of structure delineation and density assigning. Furthermore, the amalgam density data were corrected to provide amalgam voxel with accurate density value. As for the errors of dose uncertainties due to metal amalgam, they were reduced from 46% to as low as 2% at d80 (depth of the 80% dose beyond Zmax) using the presented strategies. Considering the number of vital and radiosensitive organs in the head and the neck regions, this correction strategy is suggested in reducing calculation uncertainties through MC calculation.
Improvement of the butanol production selectivity and butanol to acetone ratio (B:A) by addition of electron carriers in the batch culture of a new local isolate of Clostridium acetobutylicum YM1

Nasser Al-Shorgani NK, Kalil MS, Wan Yusoff WM, Shukor H, Hamid AA

Anaerobe, 2015 Dec;36:65-72.
PMID: 26439644 DOI: 10.1016/j.anaerobe.2015.09.008

Improvement in the butanol production selectivity or enhanced butanol:acetone ratio (B:A) is desirable in acetone-butanol-ethanol (ABE) fermentation by Clostridium strains. In this study, artificial electron carriers were added to the fermentation medium of a new isolate of Clostridium acetobutylicum YM1 in order to improve the butanol yield and B:A ratio. The results revealed that medium supplementation with electron carriers changed the metabolism flux of electron and carbon in ABE fermentation by YM1. A decrease in acetone production, which subsequently improved the B:A ratio, was observed. Further improvement in the butanol production and B:A ratios were obtained when the fermentation medium was supplemented with butyric acid. The maximum butanol production (18.20 ± 1.38 g/L) was gained when a combination of methyl red and butyric acid was added. Although the addition of benzyl viologen (0.1 mM) and butyric acid resulted in high a B:A ratio of 16:1 (800% increment compared with the conventional 2:1 ratio), the addition of benzyl viologen to the culture after 4 h resulted in the production of 18.05 g/L butanol. Manipulating the metabolic flux to butanol through the addition of electron carriers could become an alternative strategy to achieve higher butanol productivity and improve the B:A ratio.

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