Kunimitsu Kaya

Thraustochytrid Aurantiochytrium sp. 18W-13a Accummulates High Amounts of Squalene

Here we report on the 18W-13a strain of Aurantiochytrium sp., which accumulates very high amounts of squalene. The squalene contents and production at 4 d of culture were 198 mg/g and 1.29±0.13 g/L, respectively, exceptionally high values compared to previous reports.

Optimization of culture conditions of the thraustochytrid Aurantiochytrium sp. strain 18W-13a for squalene production

Optimum conditions of temperature, salinity and glucose concentration were investigated for squalene production of the strain of Aurantiochytrium sp. 18 W-13a, with a high content of squalene. Squalene production by this strain was optimum at 25 °C, 25-50% seawater concentration and 2-6% glucose concentration. When this strain was grown in the optimum condition, the squalene content and production of approximately 171 mg/g dry weight and 0.9 g/L were much higher than that previously reported in thraustochytrids, plants and yeasts, respectively. Therefore, 18 W-13a could be used as an alternative source of commercial squalene.

Effects of soybean curd wastewater on the growth and hydrocarbon production of Botryococcus braunii strain BOT-22

A laboratory study was conducted to evaluate the possibility of using wastewater from a soybean curd manufacturing plant as a growth promoter of Botryococcus braunii strain BOT-22. Soybean curd wastewater (SCW) were added to AF-6 medium to set the final concentration to 0% (control), 1%, 2%, 5%, and 10% (v/v). The growth and hydrocarbon production observed in the cultures with 1% and 2% SCW were significantly higher than that observed in the control. It was postulated that proteins and/or reducing sugars in SCW could enhance the growth. A major finding was a shift in the chemical composition of hydrocarbons from C(34)H(58) to C(32)H(54) in association with increased concentrations of SCW. Considering the inorganic ions in SCW, it was presumed that a mixture of nitrate, 1-2% SCW, and secondarily treated SCW can be applied for mass cultivation of Botryococcus.

A novel retinoic acid analogue, 7-hydroxy retinoic acid, isolated from cyanobacteria

BACKGROUND All-trans retinoic acid (RA) is a low-molecular compound derived from vitamin A. It induces events in various ways by binding with the retinoic acid receptor (RAR), a nuclear receptor, in animal cells. RA and its metabolites have been found in animal tissues. In this paper, we report a novel RA analogue found in cyanobacterial cells, describe the method for its isolation, and compare its photo-stability with that of all-trans RA. METHODS The new A analogue was extracted from cells of Microcystis aeruginosa and Spirulina sp. and fractionated by high-performance liquid chromatography. The analogue was analysed using a yeast two-hybrid assay method to measure in vitro RAR-agonistic activity. Liquid chromatography-mass spectrometry/mass spectrometry analyses was performed to elucidate the chemical structure of this RA analogue. RESULTS The results of the analysis of the fragments revealed that the novel RA analogue was 7-hydroxy RA. The yields from 3.5 μg (4.5% of the total RAR-agonistic activity of Spirulina sp. cells) of 7-hydroxy RA was a mixture of 4 isomers due to cis-trans isomerisation coupled with keto-enol tautomerism; its relative RAR agonistic activity was 0.49 ± 0.01 (n=3) when the activity of all trans RA was set up to 1.00. Under fluorescent light, the mixture of 7-hydroxy RA isomers was more stable than all- trans RA. CONCLUSIONS We isolated a novel RAR-activating compound, 7-hydroxy RA, from cyanobacteria. GENERAL SIGNIFICANCE 7-hydroxy RA is more stable than all-trans RA under UV-A.

Comprehensive study of proteins that interact with microcystin-LR

We carried out a comprehensive study of proteins that exhibit specific interactions with a naturally occurring toxin, microcystin (MC)-LR, in order to gain insight into the unknown underlying mechanism of MC virulence. This audacious study employed a simple affinity test that used MC-LR immobilized on an original ethylene oxide based monolithic solid phase (Moli-gel), and swine liver lysate. Some of the proteins that interacted with MC-LR on this original affinity resin were separated by SDS-PAGE, measured by nano-LC/MS/MS after trypsin digestion, and identified using a Mascot database search. Protein sequence analyses revealed that glutathione S-transferase (GST) was one of the candidate target proteins for MC-LR. This protein was confirmed as a target protein for MC-LR based on the results of for the inhibition of an enzymatic reaction by Dhb-MC-LR. Moreover, L-3-hydroxyacyl coenzyme A dehydrogenase (HDHA) was shown to be one of the proteins that specifically interacts with MC-LR. Our results demonstrated that our analytical systems based on an original affinity resin and nano-LC/MS/MS were effective for target protein research.

Editorial “Algae innovation”

The use of algae as an alternative of fossil fuel for the production of fuel and bulk chemicals has attracted worldwide attention in recent years. The number of algal venture businesses have been growing in Europe and USA, because it has been widely recognized that algae have enormous potential for oil production: 10–100 times higher oil production rate than terrestrial oil-crops such as rapeseeds and oil palms, and that, unlike corn and sugarcane, they are totally non-competitive with food production. Algal technology is still immature in the world, but because of such incredible potential, algae will grow to a new big market in the future. Asia-Oceania nations are expected to be the engine of the development of the world economy in the 21st century and would thereby become a mega energy consumption area in the world. In view of the problems of fuel subsidies and the reduction of carbon dioxide emissions, the promotion of the algal industry, including production of petroleum, is regarded to be the most important issue of this region. In the USA and European countries, private companies seem to have played a central role in the promoting of algal industries with strong backup from venture capitals. The situation seems to be a little different in Asia-Oceania region. Governmental, industrial and academic sectors are involved with moderate cooperation to promote algal industry. Cooperation between these sectors seems to be a common and promising way in this region to develop the