Maliwan Kutako - Academia.edu (original) (raw)
Papers by Maliwan Kutako
Journal of Applied Sciences, Aug 1, 2009
Engineering Journal, Apr 1, 2015
This study evaluated the performance of land-based compact aquaculture system integrating fibrous... more This study evaluated the performance of land-based compact aquaculture system integrating fibrous nitrifying biofilters and solid removal unit. The first experiment indicated that the compact aquaculture system with total biofilter length of 6.0 m and single solid separating was able to accommodate aquaculture weight as high as 5.0 kg/m 3 , which corresponded to nitrogen loading rates of 8.4 mg N/L/day. In the second experiment, more effective solid-liquid separation and good water quality were achieved when solid separating unit was replaced by filtration unit with Japanese mats as filtered media, and cleaning of biofilters and filtration unit was conducted in every 4 days. Next, the compact aquaculture system was employed to cultivate tilapia without water-exchange for 60 days using the described strategies. TAN and nitrite were well below acceptable limit of 1.0 mg N/L; suspended solids varied between 20 and 35 mg SS/L; and harvesting fish weights were 10.4 kg/m 3. Fish survival rate at 97% and average growth rate of 3.45 g/day were reported. Finally, solid removal remained the critical factor for successful aquacultures in the compact system even under extensive or semi-intensive aquaculture cultivation, and nitrogen mass balance indicated that nitrification-denitrification were main treatment pathways while solid removal only prolonged the activity of nitrifying biofilters.
DOAJ (DOAJ: Directory of Open Access Journals), Feb 1, 2015
Lab-scale upflow bioreactor system without biomass-liquid separation unit was built to treat low-... more Lab-scale upflow bioreactor system without biomass-liquid separation unit was built to treat low-strength nitrogenous wastewater based on intermittent aeration under low-shear environment. Biomass zone formed in the absence of gas bubbles provided simultaneous biomass retention, biodegradation of nitrogenous and carbonaceous compounds, and biomass-liquid separation. Biomass zone was stable as indicated by insignificant biomass washout rates (14-29 mg VSS/day) and relatively constant biomass zone height (26-30 cm) up to the shear gradient of 1.8 s-1. Nitrogen treatment efficiency of wastewater containing 15 mg NH 4 +-N/L was 15.3±1.96% under continuous oxygen influx of 95 mg O 2 /L/day and autotrophic environment, whereas it increased significantly, 88.2±7.05%, after intermittent aeration (3 hrs air-on and 3 hrs air-off) and organic carbon source were supplied to the bioreactor system. Carbon removal efficiencies for both continuous and intermittent aeration were comparable reported at 85±1.76% and 91±2.1%, respectively.
Archives of Microbiology, Apr 5, 2023
The objective of this study was to identify morphological and molecular comparison of three marin... more The objective of this study was to identify morphological and molecular comparison of three marine Chaetoceros species using microscopic observations, sequence analysis of 18S rDNA, random amplified polymorphic DNA (RAPD-PCR) barcoding and nuclear magnetic resonance (NMR) spectroscopy. Chaetoceros were obtained from three different algae laboratories: Center of Excellence for Marine Biotechnology (CEMB), Chanthaburi Coastal Fisheries Research and Development (CHAN) and Institute of Marine Science, Burapha University (BIM). Genomic DNA for the RAPD-PCR analysis was extracted using the phenol-chloroform method, followed by 18S rDNA amplification. The blast results of 18S rDNA sequence confirmed the significantly matched to C. gracilis for Chaetoceros BIM and CHAN and C. muelleri for Chaetoceros CEMB(e-value = 0.0, identity = 99%). The RAPD-PCR results revealed differences in the three Chaetoceros isolates with polymorphisms between 30.43% and 60.00%, and Chaetoceros CEMB showed high polymorphic bands. Scanning electron microscopy revealed that Chaetoceros CEMB were larger and had larger setae compared to the other isolates (P < 0.05). The results of the NMR characterization of metabolites were consistent with the results of the sequence and morphological analyses. The concentrations of several metabolites, including chlorophyll c 1 , chlorophyll a, Myo-inositol, fucoxanthin, astaxanthin, lutein and zeaxanthin, were lower in Chaetoceros CEMB than in Chaetoceros BIM and CHAN. However, high concentrations of fatty acids, such as oleic acid, linoleic acid, α-linolenic acid and arachidic acid, were observed in all isolates. Generally, the results of this study will aid future studies examining the diversity of Chaetoceros in various cultural environments.
Journal of Applied Phycology
Kaen Kaset = Khon Kaen Agriculture Journal, 2019
Journal of Applied Sciences, 2009
Archives of Microbiology
The objective of this study was to identify morphological and molecular comparison of three marin... more The objective of this study was to identify morphological and molecular comparison of three marine Chaetoceros species using microscopic observations, sequence analysis of 18S rDNA, random amplified polymorphic DNA (RAPD-PCR) barcoding and nuclear magnetic resonance (NMR) spectroscopy. Chaetoceros were obtained from three different algae laboratories: Center of Excellence for Marine Biotechnology (CEMB), Chanthaburi Coastal Fisheries Research and Development (CHAN) and Institute of Marine Science, Burapha University (BIM). Genomic DNA for the RAPD-PCR analysis was extracted using the phenol-chloroform method, followed by 18S rDNA amplification. The blast results of 18S rDNA sequence confirmed the significantly matched to C. gracilis for Chaetoceros BIM and CHAN and C. muelleri for Chaetoceros CEMB(e-value = 0.0, identity = 99%). The RAPD-PCR results revealed differences in the three Chaetoceros isolates with polymorphisms between 30.43% and 60.00%, and Chaetoceros CEMB showed high polymorphic bands. Scanning electron microscopy revealed that Chaetoceros CEMB were larger and had larger setae compared to the other isolates (P < 0.05). The results of the NMR characterization of metabolites were consistent with the results of the sequence and morphological analyses. The concentrations of several metabolites, including chlorophyll c 1 , chlorophyll a, Myo-inositol, fucoxanthin, astaxanthin, lutein and zeaxanthin, were lower in Chaetoceros CEMB than in Chaetoceros BIM and CHAN. However, high concentrations of fatty acids, such as oleic acid, linoleic acid, α-linolenic acid and arachidic acid, were observed in all isolates. Generally, the results of this study will aid future studies examining the diversity of Chaetoceros in various cultural environments.
Walailak Journal of Science and Technology (WJST), 2018
Determinations of fatty acid profiles of five microalgae; Amphora sp., Chaetoceros sp., Melosira ... more Determinations of fatty acid profiles of five microalgae; Amphora sp., Chaetoceros sp., Melosira sp., Bellerochae sp., and Lithodesmium sp., from the east coast of Thailand were evaluated by conventional Gas Chromatography-Flame Ionization Detector (GC-FID). The results exhibited that the fatty acids suitable for biodiesel production were the most frequent entities encountered in all microalgae profiles. The GC chromatogram of fatty acid profiles in microalgae showed that both Amphora sp. and Chaetoceros sp. comprised essential omega-3 fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Additionally, this study assessed whether Fourier Transform infrared (FT-IR) microspectroscopy could be used to evaluate and monitor the biochemical compositions of microalgae, including lipid, carbohydrate, and protein profiles, by using colorimetric methods. Results showed that FT-IR spectra combined with biochemical values of lipid, carbohydrate, and protein contents were use...
This study investigated nitrogen treatment processes by natural microorganisms in sediment from w... more This study investigated nitrogen treatment processes by natural microorganisms in sediment from white shrimp (Litopenaeus vanamei) pond. The first part of this study was conducted under laboratory condition. Sediment from shrimp pond in Pathum Thani Province was packed in sediment chamber, filled with seawater, and aerated using air stone. Concentrations of ammonia, nitrite, and nitrate in water column and in sediment were monitored. Changes of bacterial diversity in the sediment were examined by PCR-DGGE analysis of 16S rRNA gene. It was found that rapid changing of salinity from 5 to 20 PSU had no effect on ammonia oxidation process while denitrification was somewhat inhibited. The dominant bacterial species such as Marinobacter and Psuedomonas disappeared after salinity changed. Low DO concentration (2.5 mg/L) significantly inhibited nitrification process and also slightly decreased the diversity of bacteria in the sediment. Addition of NaHCO3 in the sediment chambers accelerated...
Aeration is the important factor in aquacultural system due to the vital condition for all organi... more Aeration is the important factor in aquacultural system due to the vital condition for all organisms living and having an aerobic respiration in water. Generally, the mechanical surface aerators are widely used in Thailand due to their advantage for increasing DO and having the horizontal mixing of the culture pond with large-surface area. However, the low oxygen transfer efficiency (OTE) and energy performance should be considered as the main drawback of this aerator type. Regarding to this issue, the alternative aeration systems should be studied and applied. The objective of this research is to study the aeration mechanism obtained with the diffused-air aeration combined with Liquid-Film-Forming Apparatus (LFFA). The effect of gas flow rates, types and patterns of aerator installation were investigated in aquaculture pond with 10 m*10 m*1.5 m in dimension. The analytical parameters were the volumetric mass transfer coefficient (kLa), the oxygen transfer efficiency (OTE), and the ...
Lab-scale upflow bioreactor system without biomass-liquid separation unit was built to treat low-... more Lab-scale upflow bioreactor system without biomass-liquid separation unit was built to treat low-strength nitrogenous wastewater based on intermittent aeration under low-shear environment. Biomass zone formed in the absence of gas bubbles provided simultaneous biomass retention, biodegradation of nitrogenous and carbonaceous compounds, and biomass-liquid separation. Biomass zone was stable as indicated by insignificant biomass washout rates (14–29 mg VSS/day) and relatively constant biomass zone height (26–30 cm) up to the shear gradient of 1.8 s. Nitrogen treatment efficiency of wastewater containing 15 mg NH4 -N/L was 15.3±1.96% under continuous oxygen influx of 95 mg O2/L/day and autotrophic environment, whereas it increased significantly, 88.2±7.05%, after intermittent aeration (3 hrs air-on and 3 hrs air-off) and organic carbon source were supplied to the bioreactor system. Carbon removal efficiencies for both continuous and intermittent aeration were comparable reported at 85±...
Engineering Journal, 2015
This study evaluated the performance of land-based compact aquaculture system integrating fibrous... more This study evaluated the performance of land-based compact aquaculture system integrating fibrous nitrifying biofilters and solid removal unit. The first experiment indicated that the compact aquaculture system with total biofilter length of 6.0 m and single solid separating was able to accommodate aquaculture weight as high as 5.0 kg/m 3 , which corresponded to nitrogen loading rates of 8.4 mg N/L/day. In the second experiment, more effective solid-liquid separation and good water quality were achieved when solid separating unit was replaced by filtration unit with Japanese mats as filtered media, and cleaning of biofilters and filtration unit was conducted in every 4 days. Next, the compact aquaculture system was employed to cultivate tilapia without water-exchange for 60 days using the described strategies. TAN and nitrite were well below acceptable limit of 1.0 mg N/L; suspended solids varied between 20 and 35 mg SS/L; and harvesting fish weights were 10.4 kg/m 3. Fish survival rate at 97% and average growth rate of 3.45 g/day were reported. Finally, solid removal remained the critical factor for successful aquacultures in the compact system even under extensive or semi-intensive aquaculture cultivation, and nitrogen mass balance indicated that nitrification-denitrification were main treatment pathways while solid removal only prolonged the activity of nitrifying biofilters.
This study evaluated the change of inorganic nitrogen compounds in the reactor packed with sedime... more This study evaluated the change of inorganic nitrogen compounds in the reactor packed with sediment from shrimp pond (with the surface area of 0.0149 m 2) and 2.5 L of seawater (28 PSU). Powdered shrimp feed was added into the reactor as the organic carbon source. It was found that after adding 0.1 g of shrimp feed (6.7 g/m2), feed was decomposed and therefore released ammonia into the water. Ammonia was then converted to nitrate by nitrification process and nitrate was finally removed from the reactor by denitrificati on process occurred in the sediment layer. When high organic matter (1 g shrimp feed or 67 g/m2) was loaded in the reactor, accumulation of ammonia at 8.7 mg-NH4 + -N/m2/h was found and the highest ammonia concentration was up to 8 mg- NH4 + -N/L. This was assumed that organic nitrogen loading was higher than the carrying capacity of the sediment from shrimp pond.
The objective of this study was to identify Chaetoceros species using microscopic observations, s... more The objective of this study was to identify Chaetoceros species using microscopic observations, sequence analysis of 18S rDNA, random amplified polymorphic DNA (RAPD) barcoding and nuclear magnetic resonance (NMR) spectroscopy. Chaetoceros were obtained from three different algae laboratories: Center of Excellence for Marine Biotechnology (CEMB), Chanthaburi Coastal Fisheries Research and Development (CHAN) and Institute of Marine Science, Burapha University (BIM). Genomic DNA for the RAPD analysis was extracted using the phenol-chloroform method, followed by 18S rDNA amplification. The 18S rDNA sequence analysis showed that Chaetoceros CEMB was most similar to C. gracilis (e-value = 0.0, identity = 98%), Chaetoceros CHAN was most similar to C. debilis (e-value = 0.0, identity = 99%) and Chaetoceros BIM was most similar to C. debilis (e-value = 0.0, identity = 98%). The RAPD results revealed differences in the three Chaetoceros isolates with polymorphisms between 30.43% and 60.00%, ...
Journal of Applied Sciences, Aug 1, 2009
Engineering Journal, Apr 1, 2015
This study evaluated the performance of land-based compact aquaculture system integrating fibrous... more This study evaluated the performance of land-based compact aquaculture system integrating fibrous nitrifying biofilters and solid removal unit. The first experiment indicated that the compact aquaculture system with total biofilter length of 6.0 m and single solid separating was able to accommodate aquaculture weight as high as 5.0 kg/m 3 , which corresponded to nitrogen loading rates of 8.4 mg N/L/day. In the second experiment, more effective solid-liquid separation and good water quality were achieved when solid separating unit was replaced by filtration unit with Japanese mats as filtered media, and cleaning of biofilters and filtration unit was conducted in every 4 days. Next, the compact aquaculture system was employed to cultivate tilapia without water-exchange for 60 days using the described strategies. TAN and nitrite were well below acceptable limit of 1.0 mg N/L; suspended solids varied between 20 and 35 mg SS/L; and harvesting fish weights were 10.4 kg/m 3. Fish survival rate at 97% and average growth rate of 3.45 g/day were reported. Finally, solid removal remained the critical factor for successful aquacultures in the compact system even under extensive or semi-intensive aquaculture cultivation, and nitrogen mass balance indicated that nitrification-denitrification were main treatment pathways while solid removal only prolonged the activity of nitrifying biofilters.
DOAJ (DOAJ: Directory of Open Access Journals), Feb 1, 2015
Lab-scale upflow bioreactor system without biomass-liquid separation unit was built to treat low-... more Lab-scale upflow bioreactor system without biomass-liquid separation unit was built to treat low-strength nitrogenous wastewater based on intermittent aeration under low-shear environment. Biomass zone formed in the absence of gas bubbles provided simultaneous biomass retention, biodegradation of nitrogenous and carbonaceous compounds, and biomass-liquid separation. Biomass zone was stable as indicated by insignificant biomass washout rates (14-29 mg VSS/day) and relatively constant biomass zone height (26-30 cm) up to the shear gradient of 1.8 s-1. Nitrogen treatment efficiency of wastewater containing 15 mg NH 4 +-N/L was 15.3±1.96% under continuous oxygen influx of 95 mg O 2 /L/day and autotrophic environment, whereas it increased significantly, 88.2±7.05%, after intermittent aeration (3 hrs air-on and 3 hrs air-off) and organic carbon source were supplied to the bioreactor system. Carbon removal efficiencies for both continuous and intermittent aeration were comparable reported at 85±1.76% and 91±2.1%, respectively.
Archives of Microbiology, Apr 5, 2023
The objective of this study was to identify morphological and molecular comparison of three marin... more The objective of this study was to identify morphological and molecular comparison of three marine Chaetoceros species using microscopic observations, sequence analysis of 18S rDNA, random amplified polymorphic DNA (RAPD-PCR) barcoding and nuclear magnetic resonance (NMR) spectroscopy. Chaetoceros were obtained from three different algae laboratories: Center of Excellence for Marine Biotechnology (CEMB), Chanthaburi Coastal Fisheries Research and Development (CHAN) and Institute of Marine Science, Burapha University (BIM). Genomic DNA for the RAPD-PCR analysis was extracted using the phenol-chloroform method, followed by 18S rDNA amplification. The blast results of 18S rDNA sequence confirmed the significantly matched to C. gracilis for Chaetoceros BIM and CHAN and C. muelleri for Chaetoceros CEMB(e-value = 0.0, identity = 99%). The RAPD-PCR results revealed differences in the three Chaetoceros isolates with polymorphisms between 30.43% and 60.00%, and Chaetoceros CEMB showed high polymorphic bands. Scanning electron microscopy revealed that Chaetoceros CEMB were larger and had larger setae compared to the other isolates (P < 0.05). The results of the NMR characterization of metabolites were consistent with the results of the sequence and morphological analyses. The concentrations of several metabolites, including chlorophyll c 1 , chlorophyll a, Myo-inositol, fucoxanthin, astaxanthin, lutein and zeaxanthin, were lower in Chaetoceros CEMB than in Chaetoceros BIM and CHAN. However, high concentrations of fatty acids, such as oleic acid, linoleic acid, α-linolenic acid and arachidic acid, were observed in all isolates. Generally, the results of this study will aid future studies examining the diversity of Chaetoceros in various cultural environments.
Journal of Applied Phycology
Kaen Kaset = Khon Kaen Agriculture Journal, 2019
Journal of Applied Sciences, 2009
Archives of Microbiology
The objective of this study was to identify morphological and molecular comparison of three marin... more The objective of this study was to identify morphological and molecular comparison of three marine Chaetoceros species using microscopic observations, sequence analysis of 18S rDNA, random amplified polymorphic DNA (RAPD-PCR) barcoding and nuclear magnetic resonance (NMR) spectroscopy. Chaetoceros were obtained from three different algae laboratories: Center of Excellence for Marine Biotechnology (CEMB), Chanthaburi Coastal Fisheries Research and Development (CHAN) and Institute of Marine Science, Burapha University (BIM). Genomic DNA for the RAPD-PCR analysis was extracted using the phenol-chloroform method, followed by 18S rDNA amplification. The blast results of 18S rDNA sequence confirmed the significantly matched to C. gracilis for Chaetoceros BIM and CHAN and C. muelleri for Chaetoceros CEMB(e-value = 0.0, identity = 99%). The RAPD-PCR results revealed differences in the three Chaetoceros isolates with polymorphisms between 30.43% and 60.00%, and Chaetoceros CEMB showed high polymorphic bands. Scanning electron microscopy revealed that Chaetoceros CEMB were larger and had larger setae compared to the other isolates (P < 0.05). The results of the NMR characterization of metabolites were consistent with the results of the sequence and morphological analyses. The concentrations of several metabolites, including chlorophyll c 1 , chlorophyll a, Myo-inositol, fucoxanthin, astaxanthin, lutein and zeaxanthin, were lower in Chaetoceros CEMB than in Chaetoceros BIM and CHAN. However, high concentrations of fatty acids, such as oleic acid, linoleic acid, α-linolenic acid and arachidic acid, were observed in all isolates. Generally, the results of this study will aid future studies examining the diversity of Chaetoceros in various cultural environments.
Walailak Journal of Science and Technology (WJST), 2018
Determinations of fatty acid profiles of five microalgae; Amphora sp., Chaetoceros sp., Melosira ... more Determinations of fatty acid profiles of five microalgae; Amphora sp., Chaetoceros sp., Melosira sp., Bellerochae sp., and Lithodesmium sp., from the east coast of Thailand were evaluated by conventional Gas Chromatography-Flame Ionization Detector (GC-FID). The results exhibited that the fatty acids suitable for biodiesel production were the most frequent entities encountered in all microalgae profiles. The GC chromatogram of fatty acid profiles in microalgae showed that both Amphora sp. and Chaetoceros sp. comprised essential omega-3 fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Additionally, this study assessed whether Fourier Transform infrared (FT-IR) microspectroscopy could be used to evaluate and monitor the biochemical compositions of microalgae, including lipid, carbohydrate, and protein profiles, by using colorimetric methods. Results showed that FT-IR spectra combined with biochemical values of lipid, carbohydrate, and protein contents were use...
This study investigated nitrogen treatment processes by natural microorganisms in sediment from w... more This study investigated nitrogen treatment processes by natural microorganisms in sediment from white shrimp (Litopenaeus vanamei) pond. The first part of this study was conducted under laboratory condition. Sediment from shrimp pond in Pathum Thani Province was packed in sediment chamber, filled with seawater, and aerated using air stone. Concentrations of ammonia, nitrite, and nitrate in water column and in sediment were monitored. Changes of bacterial diversity in the sediment were examined by PCR-DGGE analysis of 16S rRNA gene. It was found that rapid changing of salinity from 5 to 20 PSU had no effect on ammonia oxidation process while denitrification was somewhat inhibited. The dominant bacterial species such as Marinobacter and Psuedomonas disappeared after salinity changed. Low DO concentration (2.5 mg/L) significantly inhibited nitrification process and also slightly decreased the diversity of bacteria in the sediment. Addition of NaHCO3 in the sediment chambers accelerated...
Aeration is the important factor in aquacultural system due to the vital condition for all organi... more Aeration is the important factor in aquacultural system due to the vital condition for all organisms living and having an aerobic respiration in water. Generally, the mechanical surface aerators are widely used in Thailand due to their advantage for increasing DO and having the horizontal mixing of the culture pond with large-surface area. However, the low oxygen transfer efficiency (OTE) and energy performance should be considered as the main drawback of this aerator type. Regarding to this issue, the alternative aeration systems should be studied and applied. The objective of this research is to study the aeration mechanism obtained with the diffused-air aeration combined with Liquid-Film-Forming Apparatus (LFFA). The effect of gas flow rates, types and patterns of aerator installation were investigated in aquaculture pond with 10 m*10 m*1.5 m in dimension. The analytical parameters were the volumetric mass transfer coefficient (kLa), the oxygen transfer efficiency (OTE), and the ...
Lab-scale upflow bioreactor system without biomass-liquid separation unit was built to treat low-... more Lab-scale upflow bioreactor system without biomass-liquid separation unit was built to treat low-strength nitrogenous wastewater based on intermittent aeration under low-shear environment. Biomass zone formed in the absence of gas bubbles provided simultaneous biomass retention, biodegradation of nitrogenous and carbonaceous compounds, and biomass-liquid separation. Biomass zone was stable as indicated by insignificant biomass washout rates (14–29 mg VSS/day) and relatively constant biomass zone height (26–30 cm) up to the shear gradient of 1.8 s. Nitrogen treatment efficiency of wastewater containing 15 mg NH4 -N/L was 15.3±1.96% under continuous oxygen influx of 95 mg O2/L/day and autotrophic environment, whereas it increased significantly, 88.2±7.05%, after intermittent aeration (3 hrs air-on and 3 hrs air-off) and organic carbon source were supplied to the bioreactor system. Carbon removal efficiencies for both continuous and intermittent aeration were comparable reported at 85±...
Engineering Journal, 2015
This study evaluated the performance of land-based compact aquaculture system integrating fibrous... more This study evaluated the performance of land-based compact aquaculture system integrating fibrous nitrifying biofilters and solid removal unit. The first experiment indicated that the compact aquaculture system with total biofilter length of 6.0 m and single solid separating was able to accommodate aquaculture weight as high as 5.0 kg/m 3 , which corresponded to nitrogen loading rates of 8.4 mg N/L/day. In the second experiment, more effective solid-liquid separation and good water quality were achieved when solid separating unit was replaced by filtration unit with Japanese mats as filtered media, and cleaning of biofilters and filtration unit was conducted in every 4 days. Next, the compact aquaculture system was employed to cultivate tilapia without water-exchange for 60 days using the described strategies. TAN and nitrite were well below acceptable limit of 1.0 mg N/L; suspended solids varied between 20 and 35 mg SS/L; and harvesting fish weights were 10.4 kg/m 3. Fish survival rate at 97% and average growth rate of 3.45 g/day were reported. Finally, solid removal remained the critical factor for successful aquacultures in the compact system even under extensive or semi-intensive aquaculture cultivation, and nitrogen mass balance indicated that nitrification-denitrification were main treatment pathways while solid removal only prolonged the activity of nitrifying biofilters.
This study evaluated the change of inorganic nitrogen compounds in the reactor packed with sedime... more This study evaluated the change of inorganic nitrogen compounds in the reactor packed with sediment from shrimp pond (with the surface area of 0.0149 m 2) and 2.5 L of seawater (28 PSU). Powdered shrimp feed was added into the reactor as the organic carbon source. It was found that after adding 0.1 g of shrimp feed (6.7 g/m2), feed was decomposed and therefore released ammonia into the water. Ammonia was then converted to nitrate by nitrification process and nitrate was finally removed from the reactor by denitrificati on process occurred in the sediment layer. When high organic matter (1 g shrimp feed or 67 g/m2) was loaded in the reactor, accumulation of ammonia at 8.7 mg-NH4 + -N/m2/h was found and the highest ammonia concentration was up to 8 mg- NH4 + -N/L. This was assumed that organic nitrogen loading was higher than the carrying capacity of the sediment from shrimp pond.
The objective of this study was to identify Chaetoceros species using microscopic observations, s... more The objective of this study was to identify Chaetoceros species using microscopic observations, sequence analysis of 18S rDNA, random amplified polymorphic DNA (RAPD) barcoding and nuclear magnetic resonance (NMR) spectroscopy. Chaetoceros were obtained from three different algae laboratories: Center of Excellence for Marine Biotechnology (CEMB), Chanthaburi Coastal Fisheries Research and Development (CHAN) and Institute of Marine Science, Burapha University (BIM). Genomic DNA for the RAPD analysis was extracted using the phenol-chloroform method, followed by 18S rDNA amplification. The 18S rDNA sequence analysis showed that Chaetoceros CEMB was most similar to C. gracilis (e-value = 0.0, identity = 98%), Chaetoceros CHAN was most similar to C. debilis (e-value = 0.0, identity = 99%) and Chaetoceros BIM was most similar to C. debilis (e-value = 0.0, identity = 98%). The RAPD results revealed differences in the three Chaetoceros isolates with polymorphisms between 30.43% and 60.00%, ...