Development of a New Fermentation Process for Hardly Degradable Rice Straw Agriculture Waste (Advanced Studies on Sustainable Animal Production: Interrelationships among Human, Animal and Environment, 8th International Symposium of Integrated Field Science)

Oral Sessio

Development of a High-Efficiency Methane Fermentation Process for Hardly Degradable Rice Straw

Symposium Pape

Study on toxigenic cyanobacteria of aquaculture ponds in Thailand

Proliferation of cyanobacteria is frequently encountered in natural eutrophicated lakes as well as in aquaculture ponds, since daily feeding contributes to the high nutrient loading for the intensive aquaculture. The extensive growth of cyanobacteria presents a considerable threat to human health because many species have the potential to produce cyanotoxin. Microcystis, in particular, is a typical bloom-forming cyanobacterial genus that produces a strong hepatotoxin microcystin. In this study, aquaculture ponds of catfish and tilapia in Thailand were surveyed to obtain the basic information on the occurrence of harmful cyanobacteria and cyanotoxins. This study provided two significant facets of information. One, from a viewpoint of the evaluation of the risk of cyanotoxins in aquaculture; the other, on the ecological study of toxigenic cyanobacteria at various environmental conditions. The relationship between the proliferation of toxigenic cyanobacteria and environmental conditions such as nutrients, temperature and kinds of cultured fish in aquaculture ponds were illuminated by mainly using conventional water quality analysis, quantitative real time PCR method (a molecular ecological method) and linear model analysis for the results. The results were summarized as follows. In September and December of 2009 and March of 2010, 22 ponds for commercial farming of Nile tilapia (Oreochromis niloticus) and 17 ponds for hybrid catfish (Clarias macrocephalus x C. gariepinus) were surveyed in the provinces of Chiang Mai, Chiang Rai and Phayao. Fish species (tilapia or catfish) did not significantly affect the occurrence of toxigenic cyanobacteria. Actually, mcyD gene was detected in 8 tilapia ponds and 11 catfish ponds. Then microcystin analyzed by HPLC was detected in only 4 tilapia ponds and 6 catfish ponds. However, these differences between catfish pond and tilapia pond were not statistical significant. On the other hands, chl-a, as a surrogate of total biomass of phytoplankton, depended on both T-N and T-P. Then the concentration of chl-a in high temperature season (March) was higher than that in low temperature season (December). On the other hand, total cyanobacteria mainly depended on T-P, then it was found much in December than in March. The detection probability of mcyD in aquaculture ponds was explained by a logistic model, mainly with T-P. The probability in March was lower than that in December

Compensation of blue phase I by blue phase II in optoeletronic device

Compensation effect of blue phase I (BP I) with blue phase II (BP II) liquid crystal was demonstrated. BP I and BP II were co-exist in the optoeletronic device by polymer stabilization. Consequently, disadvantages of BP I and BP II were greatly improved by compensation effect and resulted in high contrast ratio, low hysteresis and fast falling time. Mechanism of compensation effect was explained by relaxation ability of lattice structure under electrical field and compensation structure was well confirmed by Bragg\u27s reflectance spectrum and Commission International de l\u27Eclairage chromaticity diagram

Utilization of lignin in empty fruit bunch for production of fine chemicals: development of subcritical water technology and ΔpcaHG-ΔcatA Rhodococcus jostii RHA1

Lignin is an alternative source of chemicals particularly phenolic compounds if it could broken down into smaller molecular units. Subcritical water (SCW) is a known technology that has the ability to break down lignin by hydrolysis. In this study, the SCW depolymerizes empty fruit bunch derived lignin into a mixture of aromatic compounds. The mixture, however, is impractical to be utilized and the cost to separate each of the components is relatively high. Rhodococcus jostii RHA1 is a bacterium that can degrade a wide range of aromatic compounds. Specific gene deletion of RHA1 has shown that the RHA1 loses its ability to catabolize specific chemicals. This research project aims to utilize empty fruit bunch derived lignin via SCW technology and subsequently biological process using mutant Rhodococcus jostii RHA1, ΔpcaHG-ΔcatA mutant RHA1

Microbial diversity in disturbed and undisturbed peat swamp forest and isolation of cyanobacteria

Microbial diversity from disturbed and undisturbed peat swamp forest obtained from next generation sequencing. Through this analysis, genera cyanobacteria is being compared with isolated cyanobacteria from both environmments which is extremely acidic. For the future study, this genera has ability as biofertilizer in acidic soil for plantations

Whole-Genome Sequence of the Microcystin-Degrading Bacterium Sphingopyxis sp. Strain C-1

This report describes the whole-genome sequence of an alkalitolerant microcystin-degrading bacterium, Sphingopyxis sp. strain C-1, isolated from a lake in China

Characteristics of a Microcystin-Degrading Bacterium under Alkaline Environmental Conditions

The pH of the water associated with toxic blooms of cyanobacteria is typically in the alkaline range; however, previously only microcystin-degrading bacteria growing in neutral pH conditions have been isolated. Therefore, we sought to isolate and characterize an alkali-tolerant microcystin-degrading bacterium from a water bloom using microcystin-LR. Analysis of the 16S rRNA gene sequence revealed that the isolated bacterium belonged to the genus Sphingopyxis, and the strain was named C-1. Sphingopyxis sp. C-1 can grow; at pH 11.0; however, the optimum pH for growth was pH 7.0. The microcystin degradation activity of the bacterium was the greatest between pH 6.52 and pH 8.45 but was also detected at pH 10.0. The mlrA homolog encoding the microcystin-degrading enzyme in the C-1 strain was conserved. We concluded that alkali-tolerant microcystin-degrading bacterium played a key role in triggering the rapid degradation of microcystin, leading to the disappearance of toxic water blooms in aquatic environments

Characterization of musty odor producing actinomycetes in Malaysia

The presence of geosmin and 2-methylisoborneol (2-MIB) becomes an increasing concern as they are known to cause earthy or musty odor in freshwater environments. Geosmin and 2-MIB outbreaks in Malaysia are not well understood and since Malaysia has a stable temperature throughout the year, no information has been reported on effect of temperature to the odor production. In this study, 6 isolated strains were selected for study of the effect of temperature (20, 25, 30, 35, 40, 45 & 50°C) on geosmin and 2-MIB production. Preliminary results indicate that at temperature 30 °C, Strain 5 showed highest geosmin production (129.06 µg/L) and Strain 2 produced highest 2-MIB (19.89 µg/L). PCR band was obtained in a test whether these isolated strains had geoA gene or not

Microcystin degradation in sphingopyxis sp. C-1

The microcystin-degrading gene cluster, mlrA-B-C-D, plaies an important role in the degradation process of hepatotoxic microcystins for several bacterial species. However after microcystin is degraded to linear-microcystin by MlrA, it is still unknown about where and by what it is metabolited. In order to clarify it, we disrupted the mlrB gene and mlrC gene in chromosome of microcystin-degrading bacteria, Sphingopyxis sp. C-1. The cells disrupted mlrB gene and mlrC gene accumulated of microcystin-degradation product, linear-microcystin and tetrapeptide, respectively, whereas the cell free extracts of ?mlrB cells detected Adda and ?mlrC cells accumulated tetrapeptide. Moreover, topology analysis of MlrB using the ß-lactamase gene fusion method insisted MlrB is the peripheral protein binding the inner-membrane. These results insist that MlrB degrades the linear microcystin in the periplasmic space and MlrC degrades tetrapeptide in cytoplasm. Thus, in intact cells, MlrC cannot degrade linear-microcystin as being separated in inner-membrane from linear-microcystin while MlrC is capable of degrading the linear-microcystin in cell-free extract