KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/kmitl/1

Browse

Search Results

Now showing 1 - 4 of 4

Some of the metrics are blocked by your
consent settings
Enhanced Hydrogen Production by the Halotolerant Cyanobacterium Aphanothece halophytica Through Bacterial Co-Cultivation
(2026-05-01)
Somsin, Chutikarn
;
Chinchusak, Nattanon
;
Incharoensakdi, Aran
;
Phunpruch, Saranya
Hydrogen (H<inf>2</inf>) is a promising clean energy carrier with the potential to partially replace fossil fuels. Biological H<inf>2</inf> production using microorganisms offers an environmentally friendly alternative. The halotolerant cyanobacterium Aphanothece halophytica can produce H<inf>2</inf> under nitrogen-deprived and dark anaerobic conditions. In this study, a co-culture strategy was investigated to enhance H<inf>2</inf> production. Five bacterial strains were screened for their ability to improve H<inf>2</inf> production when co-cultivated with A. halophytica. Among them, Staphylococcus aureus significantly enhanced H<inf>2</inf> production, achieving a maximum rate of 11.11 ± 0.18 µmol H<inf>2</inf> g−1 dry weight h−1. Optimization of the bacterial partner revealed that S. aureus cells harvested at 12 h in the mid-logarithmic phase with an OD<inf>600</inf> of 4.0 were the most effective. An inoculum ratio of A. halophytica to S. aureus of 4:1 further enhanced H<inf>2</inf> production, increased bidirectional hydrogenase activity, and reduced O<inf>2</inf> accumulation. Under optimal conditions (0.945 mmol C-atom L−1 glucose, 0.25 M NaCl, pH 7.4, and 35 °C), the maximum H<inf>2</inf> production rate reached 132.49 ± 4.45 µmol H<inf>2</inf> g−1 dry weight h−1, approximately 5.5-fold higher than that under normal conditions. The co-culture achieved a cumulative H<inf>2</inf> yield of 3248.51 ± 88.11 µmol H<inf>2</inf> g−1 dry weight after 48 h.
2
Some of the metrics are blocked by your
consent settings
Light-Emitting Diode Illumination Enhances Biomass, Pigment, and Lipid Production in Halotolerant Cyanobacterium Aphanothece halophytica
(2025-06-01)
Thongtha, Sitthichai
;
Kittiwongwattana, Chokchai
;
Incharoensakdi, Aran
;
Phunpruch, Saranya
Light characteristics, including spectrum and intensity, significantly impact cyanobacterial biomass production, pigment biosynthesis, and cellular metabolism, influencing the composition of various biochemical compounds. This study aimed to investigate the effects of light-emitting diode (LED) illumination on biomass, pigment, and lipid production in the unicellular halotolerant cyanobacterium Aphanothece halophytica, cultivated in a suitable natural seawater (SNSW) medium. The results revealed that LED light outperformed fluorescent light, with blue LED light, particularly at an intensity of 60 μmol photons m−2 s−1, significantly enhancing growth, pigment synthesis, and lipid accumulation. This resulted in a maximum cell density of 68.96 ± 1.52 × 106 cells mL−1, a specific growth rate of 0.302 ± 0.002 day−1, and a lipid productivity of 56.81 ± 0.75 mg L−1 day−1. White LED light produced lipids suitable for biodiesel, whereas blue, green, and red LEDs promoted the accumulation of polyunsaturated fatty acids (PUFAs), beneficial for food supplements. These findings highlight the potential of LED-based cultivation strategies for optimizing biomass and biochemical compound production in A. halophytica.
Some of the metrics are blocked by your
consent settings
Simazine Enhances Dark Fermentative H2 Production by Unicellular Halotolerant Cyanobacterium Aphanothece halophytica
(2022-07-15)
Pansook, Sunisa
;
Incharoensakdi, Aran
;
Phunpruch, Saranya
The halotolerant cyanobacterium Aphanothece halophytica is a potential H<inf>2</inf> producer that induces H<inf>2</inf> evolution under nitrogen deprivation. H<inf>2</inf> is mainly produced via the catabolism of stored glycogen under dark anaerobic condition. H<inf>2</inf> evolution is catalyzed by O<inf>2</inf>-sensitive bidirectional hydrogenase. The aim of this study was to improve H<inf>2</inf> production by A. halophytica using various kinds of inhibitors. Among all types of inhibitors, simazine efficiently promoted the highest H<inf>2</inf> production under dark conditions. High simazine concentration and long-term incubation resulted in a decrease in cell and chlorophyll concentrations. The optimal simazine concentration for H<inf>2</inf> production by A. halophytica was 25 µM. Simazine inhibited photosynthetic O<inf>2</inf> evolution but promoted dark respiration, resulting in a decrease in O<inf>2</inf> level. Hence, the bidirectional hydrogenase activity and H<inf>2</inf> production was increased. A. halophytica showed the highest H<inf>2</inf> production rate at 58.88 ± 0.22 µmol H<inf>2</inf> g−1 dry weight h−1 and H<inf>2</inf> accumulation at 356.21 ± 6.04 μmol H<inf>2</inf> g−1 dry weight after treatment with 25 µM simazine under dark anaerobic condition for 2 and 24 h, respectively. This study demonstrates the potential of simazine for the enhancement of dark fermentative H<inf>2</inf> production by A. halophytica.
Some of the metrics are blocked by your
consent settings
The Allelopathic Activity of Extracts and Isolated from Spirulina platensis
(2022-06-01)
Charoenying, Patchanee
;
Laosinwattana, Chamroon
;
Chotsaeng, Nawasit
We determined the allelopathic effects of crude organic (hexane, ethyl acetate, and methanol) extracts of the cyanobacterial Spirulina platensis on barnyardgrass (Echinochloa crus-galli (L.) Beauv.) and Chinese amaranth (Amaranthus tricolor L.). The crude ethyl acetate extract showed the highest inhibitory activity and was subsequently fractionated by column chromatography into 23 fractions based on thin-layer chromatography band pattern similarities. Four concentrations (2000, 1000, 500, and 250 ppm) of each fraction were tested for their allelopathic activity. Fractions E6 and E13 exhib-ited the most significant inhibitory effects against Chinese amaranth. The constituents of the highly active E6F3-E6F5 fractions determined by GC-MS, chromatography, and spectroscopy included the fatty acids, γ-linolenic acid 15, oleic acid 12, and predominantly palmitic acid 7; minor constituents included 2-ethyl-3-methylmaleimide 9 and C<inf>11</inf> norisoprenoids (dihydroactinidiolide 10 and 4-oxo-β-ionone 13). Isolation of E13 fraction by column chromatography revealed four C<inf>13</inf> norisoprenoids: 3-hydroxy-β-ionone 17, 3-hydroxy-5α,6α-epoxy-β-ionone 18, 3-hydroxy-5β,6β-epoxy-β-ionone 19, and loliolide 20. Their structures were elucidated by NMR spectroscopy. All six isolated noriso-prenoids inhibited seed germination and seedling growth of Chinese amaranth at concentrations of 250–1000 ppm. Allelochemicals from S. platensis could be utilized in the development of novel bioactive herbicides.
1

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results