Biohydrogen production by a novel thermotolerant photosynthetic bacterium Rhodopseudomonas pentothenatexigens strain KKU-SN1/1

Thirty-nine purple non-sulfur bacteria (PNSB) were isolated from 162 environmental samples. These isolates of PNSB were tested for their ability to produce biohydrogen (Bio-H₂) at 40 °C and only 14 isolates were noted to possess such ability, which were considered as thermotolerant photosynthetic Bio-H₂ producing bacteria (tt-PHPB). Of 14 isolates of tt-PHPB, KKU-SN1/1 was observed to have the highest Bio-H₂ productivity. Central composite design was employed to optimize the operating conditions for maximal Bio-H₂ production by the strain KKU-SN1/1. Under optimal conditions (7.6 g/L malic acid, 11 g/L glutamic acid, pH 6.7, at 40 °C) the Bio-H₂ production was increased by 68.28%. The purity of Bio-H₂ produced was 92.22%, as suggested by gas chromatography (GC-TCD). Based on morphological characteristics and 16S rDNA sequence analysis, the strain KKU-SN1/1 was identified as Rhodopseudomonas pentothenatexigens, with 99.7% similarity. To our knowledge, this is the first report on Bio-H₂ production by R. pentothenatexigens KKU-SN1/1.     

A GIS-based tool to estimate carbon stock related to changes in land use due to tourism in Phuket Island,Thailand

Clean Technologies and Environmental Policy - According to the National Statistical Office (NSO), Phuket receives a large and increasing number of visitors each year, generating revenue and...     

Properties and antimicrobial activity of edible films incorporated with kiam wood (Cotyleobium lanceotatum) extract

The antimicrobial properties of wood extracts are well known; however their application to edible films is limited. In this study, the minimum bactericidal concentration (MBC) of kiam wood extract was established as 300 mg/L at which bacterial growth was completely inhibited. The antimicrobial properties of hydroxypropyl methylcellulose (HPMC) films containing 1-5 fold of MBC of kiam wood extract were tested against Escherichia coli O175:H7, Staphylococcus aureus and Listeria monocytogenes. The edible films containing kiam wood extract exhibited more effective impact on the growth reduction of L. monocytogenes than S. aureus and E. coli (p < 0.05). The use of kiam wood extract at 1 and 2 fold of MBC incorporated into edible HPMC films did not exhibit any antimicrobial activity. However, the inhibitory effect of edible HPMC films containing kiam wood extract was observed at 3, 4 and 5 fold of MBC. The greatest zone of inhibition was observed at 5 fold of MBC incorporated in edible HPMC films. Tensile strength and elongation at break significantly decreased with the incorporation of kiam wood extract, whereas water vapor permeability and film solubility increased. The color of edible films became darker and more reddish-yellowish as well as having a lower transparency as the level of kiam wood extract was increased. Kiam wood extract incorporated in edible film provided the films with a rougher surface than pure edible film. Our results pointed out that the incorporation of kiam wood extract as a natural antibacterial agent has potential for use in extending the shelf life of food products.     

S-Scheme α-Fe2O3/TiO2 Photocatalyst with Pd Cocatalyst for Enhanced Photocatalytic H2 Production Activity and Stability

Catalysis Letters - In this work, hematite with titanium dioxide (α-Fe2O3/TiO2) heterojunctions with palladium (Pd) nanoparticles were synthesised to improve efficiency of photocatalytic...