Succession of bacterial communities during the first 36 h of biofilm formation in coastal water was investigated at 3 approximately 15 h intervals. Three kinds of surfaces (i.e., acryl, glass, and steel substratum) were submerged in situ at Sacheon harbor, Korea. Biofilms were harvested by scraping the surfaces, and the compositions of bacterial communities were analyzed by terminal restriction fragment length polymorphism (T-RFLP), and cloning and sequencing of 16S rRNA genes. While community structure based on T-RFLP analysis showed slight differences by substratum, dramatic changes were commonly observed for all substrata between 9 and 24 h. Identification of major populations by 16S rRNA gene sequences indicated that gamma-Proteobacteria (Pseudomonas, Acinetobacter, Alteromonas, and uncultured gamma-Proteobacteria) were predominant in the community during 0 approximately 9 h, while the ratio of alpha-Proteobacteria (Loktanella, Methylobacterium, Pelagibacter, and uncultured alpha-Proteobacteria) increased 2.6 approximately 4.8 folds during 24 approximately 36 h of the biofilm formation, emerging as the most predominant group. Previously, alpha-Proteobacteria were recognized as the pioneering organisms in marine biofilm formation. However, results of this study, which revealed the bacterial succession with finer temporal resolution, indicated some species of gamma-Proteobacteria were more important as the pioneering population. Measures to control pioneering activities of these species can be useful in prevention of marine biofilm formation.
A Gram-positive, rod-shaped, spore-forming bacterium, strain S-11 T , was isolated from the activated sludge of a Bacillus-dominated wastewater treatment system in South Korea and was characterized using a polyphasic approach in order to determine its taxonomic position. Cells (0.5-0.6¾2.0-2.2 mm) were motile by means of a single subpolar flagellum. They bore ellipsoidal endospores that lay in a central position in swollen sporangia. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain S-11T was a member of the genusOceanobacillus. 16S rRNA gene sequence similarity values and DNA-DNA relatedness of strain S-11 T to the type strains of other Oceanobacillus species were less than 96.2 and 66.0 %, respectively. Strain S-11 T showed distinct differences in the G+C content of the genomic DNA (33.6 mol%). The major cellular fatty acids were iso-C 14 : 0 , iso-C 15 : 0 , anteiso-C 15 : 0 and iso-C 16 : 0 . The major isoprenoid quinone was MK-7. There were also some physiological differences in comparison with the type strains of Oceanobacillus species: tests for production of acetoin and acid production from dulcitol, erythritol, myo-inositol and sorbitol were positive. The results of DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain S-11 T from the six Oceanobacillus species and subspecies with validly published names. Strain S-11 T therefore represents a novel species, for which the name Oceanobacillus caeni sp. nov. is proposed, with the type strain S-11 T (5KCTC 13061 T 5CCUG 53534 T 5CIP 109363 T ).
This study was aimed to investigate the possibility of using raw and anaerobically-digested piggery wastewater as culture media for a green microalga Chlorella vulgaris (C. vulgaris). Due to high concentration of ammonia and dark color, the microalga did not grow well in this wastewater. In order to solve this problem, air stripping and NaOCl-treatment were applied to reduce the concentration of NH3-N and the color intensity from the wastewater. Algal growth was monitored in terms of specific growth rate, biomass productivity, and nutrient removal efficiency. As a result, C. vulgaris grew without any sign of inhibition in air-stripped and 10-folds diluted anaerobically-digested piggery wastewater with enhanced biomass productivity of 0.57 g/L•d and nutrient removal of 98.7-99.8% for NH3-N and 41.0-62.5% for total phosphorus. However, NaOCl-treatment showed no significant effect on growth of C. vulgaris, although dark color was removed greatly. Interestingly, despite that the soluble organic concentration after air stripping was still high, the biomass productivity was 4.4 times higher than BG-11. Moreover, air stripping was identically effective for raw piggery wastewater as for anaerobic digestate. Therefore, it was concluded that air stripping was a very effective method for culturing microalgae and removing nutrients from raw and anaerobically-digested piggery wastewaters.
Vocabulary plays a pivotal role in the ESL classroom. Whereas a considerable amount of research has examined effective ESL vocabulary teaching and learning, missing are studies that provide examples of how to put various research findings into practice: that is, apply them to real texts including target vocabulary items. In order to close the gap between research and practice, I reviewed a broad range of relevant literature addressing vocabulary learning. Drawing on an authentic Web reading text, in which I selected five vocabulary items as target words on the basis of my experience as a secondary English teacher in Korea, I applied vocabulary teaching strategies drawn from research findings reported in the literature to provide a model for ESL teachers when putting theory into practice.
Anaerobic digestate of piggery wastewater (ADPW) contains high concentrations of ammonia and phosphorus with unbalanced molar ratio. Thus, ammonia remains at a high level even after phosphorus is completely removed through struvite formation. In this study, both ammonia and phosphorus were recovered by adding leachate of sewage sludge ash (SSA) into ADPW. It was demonstrated that 11,600 mg L of total phosphorus and 7266.7 mg L of [Formula: see text]-P were extracted from SSA by using sulfuric acid at the HSO/SSA mass ratio of 0.35. ADPW and the leachate of SSA were mixed at the volumetric ratio of 1:1.29, and then struvite was formed at the molar ratio of 1.2 (Mg):1.0 ([Formula: see text]-P):1.0 (NH-N). Removal efficiencies of ammonia and phosphorus were 91.95% and 99.65%, respectively. The obtained struvite was analyzed by various methods and was found to meet the Korean fertilizer standards, except for copper.
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