Makkapan, Walaiporn
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Preferred name
Makkapan, Walaiporn
Alternative Name
Makkapan, W.
Main Affiliation
Email
walaiporn.ma@kmitl.ac.th
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Item type:Publication, Cellulase activity of Bacillus velezensis isolated from soil in a dairy farm(2019-10-15); The aim of the present study was to isolate and screen cellulase producing bacteria from soils including characterizing the cellulase activity of the identified bacterial strain. Screening of the cellulase producing bacteria was performed on a carboxymethylcellulose (CMC) agar (pH 7.0) plate at 37°C for 3 days. Bacterial isolate, namely CC1-1, showed the highest cellulase activity on the CMC agar plate. Subsequently, it was identified as Bacillus velezensis based on 16S rDNA gene sequence analysis. Cellulase production was carried out under submerged fermentation. The maximum CMCase and FPase activity of 0.030 U/ml and 0.047 U/ml were obtained after 20 h and 32 h, respectively. The optimal pH and temperature of CMCase activity were 6.0 and 60°C, respectively. The cellulase activities were active in a broad pH and temperature range. The CMCase activity was stable at pH 6.0-7.0, 37°C for 120 min and the stability of CMCase was revealed at 50-60°C for 90 min with over 80% remaining activity. However, the optimum pH and temperature of FPase activity were 7.0 and 50°C, respectively. The FPase activity was stable at pH 6.0, 37°C for 90 min and its activity was stable at 60°C for 60 min with over 80% remaining activity. Due to its particular properties, cellulase-producing B. velezensis could be a potential candidate for the composting process. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Determination of histamine-forming bacteria, total coliform and escherichia coli in fermented foods(2020-01-01); Fermented fishery food products have been generally sold in the local market, Thailand. These products were frequently contaminated with various microorganisms due to raw material and unhygienic production process. Determination of microbial contamination of fermented food products helps to assure safety for consumers. Therefore, the aims of the study were to determine total bacteria, total coliform, Escherichia coli and histamine producing bacteria from fermented fishery food products commercially distributed in several regions of Chumphon and Surat Thani provinces. Twenty-two samples of fermented fishery food products were randomly collected for bacterial contamination assay. All samples revealed the levels of pH and salt content in the range of 3.67-7.46 and 8.46%-29.69%, respectively. The bacterial contamination of the samples was tested by total plate count method. Determination of coliform bacteria and E. coli was examined by multiple-tube fermentation technique. Total bacteria, total coliform and E. coli of all samples were in the range of 2.15-7.54 log CFU/g, < 3-460 MPN/g and < 3-93 MPN/g, respectively. In addition, thirteen histamine-forming bacteria were found on histamine-forming bacteria isolation agar after incubation at 37°C for 4 days. Five isolates of histamine-forming bacteria named M1, M3, M9, M11, and M13 were selected to identify by molecular techniques. M1 and M3 were obtained from shrimp paste (Kapi) and M11 was obtained from fermented fish (Pla Pang Dang). They were identified as Enterobacter sp. M9 and M13 isolated from fermented fish (Pla Som and Pla Ra) were identified as Citrobacter farmeri and Staphylococcus kloosii, respectively. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Characterization of protease activity from hepatopancreas of blue crab(2019-10-15); Proteolytic enzymes play an important role in determining the quality of blue crab during postmortem storage. Activity of endogenous proteases is involved in the texture softening and autolysis of blue crab, which limits the customer acceptance and marketing price. This research aimed to characterize the protease activity of crude enzyme extract from the hepatopancreas of blue crab. The optimum activity of crude protease extract was found at pH 7.0 and 50°C. The crude protease enzyme was highly stable over a wide pH range of 4.0-11.0 and showed high stability at temperatures below 40°C. In addition, the protease activity continuously decreased with an increasing concentration of NaCl (0-15% w/v). Therefore, an understanding of the endogenous proteases in the blue crab could be used to develop appropriate storage methods during its distribution process.