李凌
摘 要:建立以主要餌料微藻的可持續育種技術體系和育種群體,培育高產、抗逆新品系,突破微藻培養廣鑒技術,構建成熟的微藻餌料工程化生產技術與工藝為目標。通過對18S rDNA、rbcL基因和ITS區序列的測定及系統進化分析,建立了微藻種間及株系間分子鑒別技術;對多株餌料微藻的生長及適應性進行了比較研究,篩選出了適應不同光強的雨生紅球藻藻株,抗逆性強的小球藻、三角褐指藻,耐高溫的纖細角毛藻藻株及鹽藻、扁藻等多株優良餌料微藻,為規?;囵B提供了良好材料。研究了微藻高密度培養中的生長指標和適應機制,并在此基礎上針對雨生紅球藻、微擬球藻、三角褐指藻、小球藻等多種餌料微藻研究了不同培養條件及添加物對其生長及營養物質積累的影響,建立了多種餌料微藻的高密度培養技術,其中微擬球藻在氣升式螺旋管道(光徑1.2 cm)光生物反應器中培養時,最高密度可達15 g/m2,比目前常規技術提高了3~4倍。針對餌料微藻的特點,設計了規模大小遞增的光生物反應器,建立了敵害生物綜合防御的方法和技術體系,有效降低污染幾率;克服了傳統封閉培養中氧氣解析、二氧化碳補償、光線分布、物料均質、細胞貼壁等難題,實現了主要參數溫度、pH值和溶解氧等
數據的在線檢測和自動控制。通過實驗室100mL-500mL-,戶外200L-多組并聯柱狀光生物反應器逐級擴大培養,建立了多種餌料微藻工程化生產工藝,建設了2個產業化基地,實現300 t體積的規模培養。以三角褐指藻、小球藻和牟氏角毛藻3種餌料型微藻為對象,通過在現有液固分離的小型設備上進行濃縮效果實驗,確定了生產型的濃縮設備并針對以上3種不同微藻的特性,進行了微藻濃縮工藝的研究,建立了不同微藻的濃縮工藝。優化了微藻產品(藻膏)低溫保存技術,形成微藻產品濃縮與保存技術規模和規范。
關鍵詞:餌料型微藻 篩選 高效培養 光生物反應器
Abstract:The aim of the program is to establish sustainable breeding technological system and group of the main bait microalgae, cultivate high-yielding, resistant strains, break through the identification technology, and build large-scale production technology of bait microalgae. The molecular identification technology of microalgae was established by phylogenetic analysis of 18S rDNA, rbcL gene and ITS sequences. Based on the comparison of growth and adaptability of multiple microalgae strains, Haematococcus pluvialis adapted to different light intensities, Chlorella sp. and Phaeodactylum tricornutum with strong stress resistance,Chaetoceros gracilis resistant to high temperature, and other good strains (e.g. Dunaliella salina and Tetraselmis sp.) were selected to provide materials for large-scale culture. The growth index and adaptation mechanism of microalgae in high density cultivation were studied, and through researching the effect of culture conditions and additives on the growth and nutrient accumulation of several microalgae (e.g. H. pluvialis, Nannochloropsis sp.,P.tricornutum,Chlorella sp.),a high-density cultivation technology were established, by which the biomass of Nannochloropsis sp.increased 3~4 times,and reached up to 15 g/m2 in airlift helical pipes photobioreactors (diameter 1.2 cm). Based on the characteristics of bait microalgae,photobioreactors with different sizes were designed, pollution risk was efficiently reduced by establishing technology for predators extermination, the traditional problem in closed culture, such as oxygen release,carbon dioxide compensation, light distribution, material homogenization, and cells attachment were overcome, and the main parameters,such as temperature, pH and dissolved oxygen data were detected online and controlled automatically.A large-scale production technology of microalgae was established through enlargement culture step by step using 100 mL to 500 mL and 200 L column photobioreactor,and two industrialization bases were built to meet the cultivation scale of 300 tons. Based on the characteristics of P.tricornutum,Chlorella sp. and Chaetoceros muelleri, concentration technology for different microalgae was established through experiment on small liquid-solid separation equipment. Cryopreservation technology of microalgae products (algae paste) was optimized, and the technical specification for concentration and preservation of microalgae products was formed.
Key Words:Bait microalgae;Screen;Efficient culture;Photobioreactor
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