• Korean Journal of Microbiology
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• v.50 no.4
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• pp.313-318
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• 2014

The world is in need of sustainable and eco-friendly energy sources such as microalgal biodiesel due to global warming and fossil fuel shortages. In this study, we compared the effectiveness of liquid fertilizer produced from swine manure and agriculture grade solid fertilizers as nutrient sources for microalgal biomass production. Mixed culture (Chlorella spp., Scenedesmus spp., Stigeoclonium spp.; CSS) was cultivated for 28 days in Small Scale Raceway Pond (SSRP) using various nutrient sources (swine manure liquid fertilizer, agricultural solid fertilizer, and mixture of these two fertilizers). Biomass and lipid productivity of fertilizer mixture were the highest at 0.8 g/L and 5.8 mg/L/day, respectively. These results indicate that the fertilizer mixture can provide microalgae necessary nutrient sources for stable biodiesel production and biomass growth. In addition, overall cost of microalgal cultivation and subsequently biodiesel production would be significantly reduced.

• KSBB Journal
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• v.29 no.4
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• pp.285-296
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• 2014

Although the problems of the algal blooms have been world-widely observed in freshwater, estuary, and marine throughout the year, it is not yet certain what are the basic causes of such blooms. Consequently, it is very difficult to predict when and where algal blooms occur. The constituents of the Asian dust are in a good agreement with the elements required for the algal growth, which suggests some possible relationship between the algal blooms and the Asian dust. There have been frequently algal blooms in drinking water from rivers or lakes. However, there is no any algal blooms in upwelling waters where the Asian dust cannot penetrate into the soil due to its relatively weak settling velocity (size of particles, $4.5{\pm}1.5{\mu}m$), which implies the possible close relationship of the Asian dust with algal blooms. The present initiative study is thus intended firstly in Korea to illustrate such a relationship by reviewing typical previous studies along with 12 years of weekly iron profiles (2001~2012) and two slant culture experiments with the dissolved Asian dust. The result showed bacterial suspected colonies in the slant culture experiment that are qualitatively in a good agreement with the recent Japanese studies. Since the diatoms require cheap energy (8%) compared to other phytoplankton (100%) to synthesize their cell walls by silicate, the present results can be used to predict algal blooms by diatoms if the concentrations of iron and silicate are available during spring and fall. It can be postulated that the algal blooms occur only if the environmental factors such as light, nutrients, calm water surface layer, temperature, and pH are simultaneously satisfied with the requirements of the micronutrients of mineral ions supplied by the Asian dust as enzymatic cofactors for the rapid bio-synthesis of the macromolecules during algal blooms. Simple eco-friendly methods to regulate the algal blooms are suggested for the initial stage of blooming with limited area: 1) to cover up the water surface with black curtain and inhibit photosynthesis during the day time, 2) to blow air (20.9%) or pure oxygen into the bottom of the water and inhibit rubisco for carbon uptake and nitrate reductase for nitrogen uptake activities in algal growth during the night, 3) to eliminate the resting spores or cysts by suction of bottom sediments as deep as 5 cm to prevent the next year germinations.