 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of High Temperature on Inhibtion of the Growth of Bacterial Wilt Pathogen (Ralstonia solanacearum) in Soil) ผู้เขียน: Jirasak Kongkiattikajorn, Tanathep Pithayarathsak, Sirichia Thepa สื่อสิ่งพิมพ์:pdf AbstractThis study was carried out to examine the efficacy of heat treatment on soil for the control of bacterial wilt (Ralstonia solanacearum). The viability of Ralstonia solanacearum was tested in both wet and dry soils under simulated elevated temperatures in either constant, cyclic or short temperature regimes. In wet soil, viability was reduced to zero by a constant temperature of 45?C and above for 2 day or a temperature of 60?C for 2 h. Viability of Ralstonia solanacearum was reduced to zero by a 2 h temperature cycle for 2 days at 50?C or 3 days at 45?C. In dry soil at 55?C, a 1-day constant temperature or at 45?C a 2 days 2- h temperature cycle reduced Ralstonia solanacearum viability by 87.5 and 37.5%, respectively. Data on time and temperature relationships on loss in viability of Ralstonia solanacearum in soil could be used to predict efficacy of soil solarization. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Study of Methane Producing Bacteria from Rice Paddy Field Soil and Rice Roots by Fluorescent In Situ Hybridization Technique) ผู้เขียน:Jirasak Kongkiattikajorn, Winai Keawsawat, Somkiatti Tachakanchanarag สื่อสิ่งพิมพ์:pdf AbstractOne of the sources of gas methane in the atmosphere causing the world warming comes from paddy fields which are the habitats of methane producing bacteria. Root zone soil and rice roots cv. Suphanburi 90 and Homsuphanburi provided by Rice Research Center Pathum Thani were studied for characterization of methane producing bacteria. The samples were inoculated in basal broth medium in serum vials under anaerobic condition and incubated at 37?C for 40 days. Methane in the vials was determined by gas chromatography. The results showed the methane producing bacteria from the soil of the paddy field of the rice cv. Suphanburi 90 and Homsuphanburi could produce methane at maximum rate of 0.7 and 0.6 ml/g/day at 17 days of incubation, respectively. The microorganisms from the rice root cv. Suphanburi 90 and Homsuphanburi could produce methane at maximum rate of 0.6 and 0.5 ml/ g/day at 22 days of incubation, respectively. On determination the type of methane producing bacteria by FISH technique, it was found that the microbacteria from rice root was characterized to be Methanosarcina sp. while the microbacteria from the soil was characterized to be Methanosatae sp. The number of the methanogenic bacteria from the soil and rice root of the rice cv. Suphanburi 90 determined by MPN method was found to be 3.49 ? 107 and 2.01 ? 103 cell/g, respectively, while the number of the methanogenic bacteria from the soil and rice root of the rice cv. Homsuphanburi was 3.75 ? 105 and 5.22 ? 103 cell/g, respectively. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of Storage Time and Temperature on Volatile Aroma Compounds and Physicochemical Properties of Rice) ผู้เขียน:Jirasak Kongkiattikajorn สื่อสิ่งพิมพ์:pdf AbstractStorage affected to physicochemical properties of Khao Dawk Mali 105 rice variety. The pasting temperature of the samples stored at 25?C decreased over time while pasting temperature of the samples stored at 37?C increased over the storage time. The colour (b) value increased according to storage temperature and the b value at 37?C was higher than the storage at 25?C. The aroma changes of rice was dued to the decreasing changes volatile compounds, 2-acetyl-1-pyrroline (2-AP) and increasing of hexanal. Storage time had a significant positive correlation with the b-value, pasting properties and a negative correlation with 2-AP content. Lower storage temperature was considered to be used to preserve 2-AP of the aromatic rice during storage. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of Storage Time and Storage Protein on Pasting Properties of Khao Dawk Mali 105 Rice Flour) ผู้เขียน:Sarawadee Wongdechsarekul, Jirasak Kongkiattikajorn สื่อสิ่งพิมพ์:pdf AbstractAging significantly affected the solubility of storage proteins and pasting properties of Khao Dawk Mali 105 rice flour. The protein solubility of rice from freshly harvested and seven-month stored rice differed significantly. The freshly harvested rice showed higher protein content (5.35 g%), whereas the storage rice showed lower protein content (4.29 g%). The protein component of rice flour from nonstored and stored rice mainly consisted of glutelin, with values of 3.86 g% and 3.09 g%, respectively. The rice flour from non-stored rice consisted of 1.00 g% globulin, 0.25% albumin and 0.23% prolamin and the rice flour from stored rice consisted of 0.74 g% globulin, 0.12% albumin and 0.34% prolamin. Aging significantly increased the pasting viscosity of rice flour, but decreased the protein solubility. Peak viscosity of non-stored rice flour decreased by 24% in dealbumin rice, by 44% in deglobulin rice and by 3% in deprolamin rice, but increased 15% in deglutelin rice. Storage might lead to a protein matrix more closely associated with the starch granules and this could explain the changes observed in the solubility and pasting properties. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Study on Activity and Stability of Native and Chemical Modified Bromoperoxidase) ผู้เขียน:Jirasak Kongkiattikajorn, Pintip Ruenwongsa สื่อสิ่งพิมพ์:pdf AbstractChemical modification of enzymes is widely used as a tool for studying localization of individual amino acids, their participation in the maintenance of the native conformation and for their catalytic activity and stabilization. In this study, two isozymes of bromoperoxidase (BPO); BPOI, BPOII; were isolated and purified from Gracilaria sp. using fast protein liquid chromatography (FPLC) method. The isozymes were characterized and modified by various chemical modifying reagents. The effects of the chemical modification on catalytic activity and stability of BPOI were studied. BPOI was inhibited by 2-hydroxy-5-nitrobenzyl bromide (HNBB), 2-nitrophenylsulfenyl chloride (NPS), N-bromosuccinimide (NBS) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). The amino groups of the enzyme were modified with iodoacetamide to change the enzyme’s structure character and to increase its hydrophobicity. This modification improved the enzyme specific activity and increased the thermostability. Chemical modification suggested involvement of Trp, Asp/Glu in the catalytic site of the enzyme due to the decrease of enzyme activity of the modified enzyme. The 2, 4, 6- trinitrobenzenesulfonic acid modification increased the catalytic activity and the iodoacetamide- modified BPOI also showed greater thermal stability and catalytic activity. The improvements of catalytic properties are related to the changes of the hydrophobicity of substituted groups of lysine residues of BPOI. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Characterization of Non-Heme Haloperoxidase from Marine Red Algae, Gracilaria sp.) ผู้เขียน:Jirasak Kongkiattikajorn, Sayampong Pongdam สื่อสิ่งพิมพ์:pdf AbstractIn this study, the haloperoxidase has been isolated from the marine red algae, Gracilaria sp. and has been characterized. Haloperoxidase requires vanadium for enzyme activity. The enzyme was purified by ion-exchange and size-exclusion chromatography. The relative molecular mass was 619 kDa, as determined by gel filtration. The UV spectrum of the peroxidase did not show absorbance in the Soret band indicating a non-heme protein, like vanadium-dependent haloperoxidases. Reconstitution experiments in the presence of several metal ions showed that only vanadium completely restored the enzyme activity. The enzyme was also moderately thermostable, keeping full activity up to 50?C for 30 min. It has a pH optimum for bromoperoxidase activity at 6.0 and exhibits activities over a broad pH range from 4.5 to 8.5 It was inhibited by ethylene diamine tetra acetic acid (EDTA). Brominating activity was noticed using monochlorodimedone (MCD) as a substrate. The preliminary steady-state kinetic study was performed and apparent Michaelis–Menten kinetic parameters were determined for the substrate monochlorodimedone. The kinetic parameter has been determined from a steady-state analysis of the bromination: Km MCD = 2.74 ? 10-4M. Enzyme was inactivated by diafiltration against 100 mM citrate-phosphate pH 3.8 buffer in the presence of 1 mM EDTA, followed by a second diafiltration with 20 mM Tris-HCl (pH 8.0). Reactivation studies were carried out with ferric chloride, manganese sulphate, manganese sulphate, potassium chloride, cobolt sulphate, nigel chloride, cupric chloride, zinc chloride and sodium vanadate in the later buffer. The thermostability of the enzyme was tested by heating the extract at 30-80?C for 30 min and checking the activity (bromide assay). The enzyme from the marine red alga, Gracilaria sp. was found to be a non-heme bromoperoxidase. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Antioxidant Properties of Roselle Vinegar Production by Mixed Culture of Acetobacter aceti and Acetobacter cerevisiae) ผู้เขียน:Jirasak Kongkiattikajorn สื่อสิ่งพิมพ์:pdf AbstractRoselle (Hibiscus sabdariffa) has been used in folk medicine and as a treatment for diseases and cancer. The objective of this study was to enhance the acetic acid production and the antioxidant activities (AOA) of Roselle vinegar using mixed culture fermentation. The Roselle wine was produced in a batch reactor. The kinetic parameters obtained for wine fermentation using Saccharomyces cerevisiae were: maximum ethanol production = 63.47 g.L-1, ethanol production rate = 2.25 g.L-1. hr-1, product (ethanol) yield coefficient = 0.45 and cell mass yield coefficient = 1.53. Using a mixed culture of Acetobacter aceti and Acetobacter cervisiae, the wine vinegar process optimization ranges for initial concentrations of ethanol and acetic acid as independent variables were 63.47 and 69.21 g.L-1, respectively. Roselle was processed into juice fermentation and vinegars. The total phenolics, total anthocyanins, and antiradical activity (1-1 diphenyl-2-picryl hydrazyl radical-scavenging (DPPH) method) were determined. Acetification increased the total anthocyanin content, total polyphenols and antioxidant activities. Correlations indicated that anthocyanins made greater significant contributions than did phenolics to the antioxidant activities of the products. The antiradical activity of wine from Roselle juice was high with an effective concentration which inhibited the DPPH activity by 50% (EC50) of 14.95 mg.L-1. The antioxidant activity of the vinegar product was high with an EC50 of 0.72 mg.L-1. The results indicated that fermentation is a better method for obtaining higher antioxidant activity of Roselle products. Furthermore, acetification significantly increased the anthocyanins and antioxidant activities. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : The Effects of Starter Cultures on Biogenic Amine and Free Amino Acid Contents in Nham during Fermentation) ผู้เขียน:Sasithorn Limsuwan, Wonnop Visessanguan, Jirasak Kongkiattikajorn สื่อสิ่งพิมพ์:pdf AbstractFermented pork sausage, or Nham, is a Thai-style fermented food which relies mainly on adventitious microorganisms, normally found in raw materials. The fermented foods usually contain biogenic amines produced by the microorganisms which caused the reaction of amino acids decarboxylation. These compounds are associated with toxicological symptoms. The objective of this study was to study the influence of two decarboxylase negative starter cultures in the presence of biogenic amines and free amino acid contents in Nham. Derivative biogenic amines by dansyl chloride were determined by high performance liquid chromatography (HPLC). Cadaverine and tyramine were determined during ripening process. The highest concentrations of biogenic amines were found at the end of the ripening process in the control sausage with no starter culture. Starter cultures test showed that Lactobacillus sakei BCC102 and Debaryomyces hansenii BCC 106 were efficient in reducing the amine production since these strains caused a quick pH drop during sausage fermentation. Total free amino acids after fermentation process decreased and the high decreases in the contents were glutamine and arginine while tyrosine and lysine, precursors for tyramine and cadaverine, respectively, increased in all batches. This study suggested that the use of decarboxylase negative lactic acid bacteria as starter cultures, which produced a rapid decrease on the pH of the meat mixture, was important factor to be considered to reduce the levels of biogenic amines in Nham. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of Salinity Stress on Degradation of Polyamines and Amine Oxidase Activity in Maize Seedlings) ผู้เขียน:Jirasak Kongkiattikajorn สื่อสิ่งพิมพ์:pdf AbstractThe objective of this study was to obtain information on the interrelation between polyamine (PA) degradation and diamine oxidase (DAO) activity under salt stress. To identify a quantitative correlation between PA degradation and DAO activity in maize under salt stress, the changes in endogenous free PA levels and DAO activity were analyzed in maize seedling roots, using treatments with different concentrations of NaCl and aminoguanidine (AG, a specific inhibitor of DAO). The results showed that the levels of putrescine (Put), cadaverine (Cad), spermidine (Spd) and spermine (Spm) decreased significantly with increasing salt concentrations. This occurred because salt stress strongly promoted DAO activity to stimulate PA degradation. AG treatment increased the accumulation of endogenous free PAs because of a strong retardation of DAO activity. A close correlation was observed between the changes in DAO activity and the PA contents among various treatments. The results indicated that salt stress could enhance PA degradation, suggesting that DAOs might increase their functions under salt stress. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Optimization of Agitation Conditions for Maximum Ethanol Production by Coculture) ผู้เขียน:Arisra Rodmui, Jirasak Kongkiattikajorn, Yuwapin Dandusitapun สื่อสิ่งพิมพ์:pdf AbstractThe coculture of Saccharomyces cerevisiae and Candida tropicalis was used for batch ethanol production in a synthetic medium containing 20 g/l glucose and xylose as carbon source. After incubation at 30 ?C for 18 h at glucose and xylose ratio 1:0, 8:1, 6:1, 4:1, 2:1, 1:1 and 0:1, the yield of ethanol (Yp/ Ss) were 0.35, 0.35, 0.34, 0.32, 0.32, 0.27 and 0.05 g/g, respectively. The yield of cell mass were 0.12, 0.09, 0.08, 0.08, 0.10, 0.09 and 0.10 g/g, respectively. The results indicated that the coculture could produce the maximum level of ethanol at the mixture of glucose and xylose ratio 8:1. Batch fermentation with agitation rate 0-200 rpm was studied using mixed glucose and xylose (8:1) under the same condition. The results showed that the yields of ethanol (Yp/Ss) were 0.33, 0.38, 0.37, 0.35 and 0.33 while the yields of cell mass were 0.04, 0.04, 0.05, 0.09 at the agitation rate of 0, 50, 100, 150 and 200, respectively. The results suggested that the agitation rate of 50 rpm was suitable for ethanol production by the coculture from the mixed sugars. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Comparative Study of Bioethanol Production from Cassava Peels by Monoculture and Co-Culture of Yeast) ผู้เขียน:Jirasak Kongkiattikajorn, Buddhiporn Sornvoraweat สื่อสิ่งพิมพ์:pdf AbstractThe feasibility of ethanol production from pretreated cassava peels by simultaneous saccharification and fermentation (SSF) with a monoculture of Saccharomyces diastaticus 2047 and S. cerevisiae 7532 and a co-culture of S. diastaticus 2047 and Candida tropicalis 5045 was studied. The results indicated that each strain of yeast was able to produce ethanol. From the cassava peels pretreated with distilled water at 135 ?C for 30 min under pressure of 1.03 bar, S. diastaticus 2047 could produce ethanol yields as high as that of pretreatment with diluted sulfuric acid under the same conditions. The cassava peels pretreated with diluted sulfuric acid and fermented by co-culture of S. diastaticus 2047 and C. tropicalis 5045 produce greater amounts of ethanol than those fermented by S. diastaticus 2047. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Role of Modified Lysine Residues on Enzyme Kinetic of Bromoperoxidase) ผู้เขียน:Jirasak Kongkiattikajorn,  นายภิญโญ พานิชพันธ์ สื่อสิ่งพิมพ์:pdf AbstractBromoperoxidase (BPO) from Thai red seaweed Gracilaria sp. has been purified and chemically modified with iodoacetamide under defined experimental conditions yielding derivatives of native bromoperoxidase. The modification increased the catalytic activity of the enzyme at concentrations of iodoacetamide up to a level of 50 mM. In order to investigate the molecular mechanism of the activation, the differences changes between native and modified enzymes were studied using kinetics methodology. The modified BPO showed greater affinity and maximal velocity for different substrates than native BPO. It has been shown that this modification reagent reacts with the ?-amino groups of the 15 out of the total 46 lysine residues of bromoperoxidase. The substrate affinity of modified BPO increased with the increases of substituents at ?-amino groups of lysine of the enzyme. The chemical modification of BPO increased its affinity for substrate monochlorodimedone (MCD) and hydrogen peroxide (about 2- and 110-fold, respectively) and also increased the maximal velocity with MCD, KBr and hydrogen peroxide (about 3-, 2.7 and 21-fold, respectively). The improvements of catalytic properties are also related to the changes in the number of ?-amino groups modified. The modification might involve neutralization of positive charges residues in BPO. The results presented in this study indicate that bromoperoxidase may acquire some new and useful characteristics related to stability and activity upon modification of specific amino acid side chains. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Increased Tomato Yields by Heat Treatment for Controlling Ralstonia solanacearum in Soil) ผู้เขียน:Jirasak Kongkiattikajorn, Sirichia Thepa สื่อสิ่งพิมพ์:pdf AbstractPossibities of soil after heat treatment by incubation at high temperature were investigated for controlling Ralstonia solanacearum, the causal agent of bacterial wilt on tomato. A constant temperature of 45?C for 2 day or a minimum temperature of 60?C for 2 h was applied in soil, after which tomato seedlings were grown. The incidence of tomato drop was very low in the heated plots, but a 40-50% loss of tomato to the disease was observed in the control plots (no heat treatment). Reductions in biomass and in the number of tomato seedlings were observed in the non heated treatments, reduced the total bacterial population by 60-97%. The populations of native Ralstonia spp. were reduced from 2.4-7?108 colony forming units (cfu)g-1 to 0-115 cfu g-1. Heat treatment reduced bacterial wilt incidence by 50- 75%. This study presented the report on the efficiency of high temperature treatment on soil against tomato bacterial wilt pathogens. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : A Study of Optimal Conditions for Reducing Sugars Production
from Cassava Peels by Diluted Acid and Enzymes) ผู้เขียน:Kanlaya Yoonan, Jirasak Kongkiattikajorn สื่อสิ่งพิมพ์:pdf AbstractCassava peels were dried and milled into small pieces. 1.5%(w/v)Cassava peel was hydrolysed
by 0.1 M sulfuric acid at 135?C under pressure 15 lb/inch2 for 90 min producing 66.28%yield of reducing
sugars while 0.025 M hydrochloric acid produced 63.29% yield of reducing sugars under the same
conditions. Hydrolysis by 0.25 M acetic acid could produce 30.36% yield of reducing sugars under
the same conditions. Enzymatic hydrolysis of 1.5% cassava peels by a-amylase at pH 6.0, 90?C for 2 hr
produced 40.79% yield of reducing sugars. After that, the reaction mixture was continuously hydrolysed
by amyloglucosidase at pH 4.0, 50?C for 24 hr, which produced 70.11% yield of reducing sugars.
Hydrolysis of 1.5% cassava peel by cellulase under optimal condition at pH 5.0, 50?C for 24 hr produced
43.39% yield of reducing sugars. Hydrolysis of 1.5% cassava peels by xylanase under optimal conditions
at pH 4.0, 50?C for 9 hr produced 2.64% yield of reducing sugars while hydrolysis by pectinase under
optimal condition at pH 5.0, 40?C for 3 hr produced 9.01% yield of reducing sugars. From this study, it
was shown that cassava peels could produce reducing sugars by dilute acid hydrolysis and that several
enzymes digestion. |