Jeeraporn Pekkoh

Reversed-phase liquid chromatographic–mass spectrometric determination of microcystin-LR in cyanobacteria blooms under alkaline conditions

Reversed-phase HPLC coupled to the atmospheric pressure ionization-electrospray ionization (API-ESI) MS was used for microcystin-LR detection and quantitation in samples of dried Microcystis aeruginosa cells. An alkaline linear gradient (20 mmol/l ammonium hydroxide-acetonitrile, pH 9.7) was used for elution of the toxic peptides. Limit of detection was 1 microg/ml (20 ng per injection) in the scan mode of MS and 0.1 microg/ml (2 ng per injection) in the case of selective ion monitoring.

Comparison of hydrogen production in microalgae under autotrophic and mixotrophic media

Abstract Hydrogen is an alternative source of energy of considerable interest, because it is environmentally friendly. Biological hydrogen production processes involving green microalgae are of significant interest. However, until present only few microalgae genera have been studied and almost all of those studies have focused only on cultivation using mixotrophic or heterotrophic media, which are expensive, and can be easily contaminated. This study aimed to compare the potential of biohydrogen production from novel green microalgae under autotrophic and mixotrophic media. A total of ninety strains of six orders of green microalgae were investigated for their capabilities of hydrogen production. The results showed that eleven novel hydrogen-producing microalgae genera were found. The hydrogen production in each order was influenced by the medium. Moreover, several strains presented notable levels of autotrophic hydrogen production and performed at over twice of the mixotrophic medium. These results should be supportive information for the selection and cultivation of hydrogen-producing microalgae in further studies.

Distribution of chlorophytic phytoplankton in Northern Thailand

The distribution of phytoplankton was investigated in standing water bodies such as reservoirs, ponds and marshes. Thirty sampling sites in Northern Thailand were studied during 1998–2005. The water quality could be classified as oligotrophic-mesotrophic to eutrophic status. Twelve families, 51 genera and 181 species of chlorophytic phytoplankton were found. The dominant genera were Staurastrum spp., Cosmarium spp., Scenedesmus spp. and Pediastrum spp. The distribution of these species was mainly affected by the water quality.