Dual potential of microalgae as a sustainable biofuel feedstock and animal feed

The rise in global population has led to explorations of alternative sources of energy and food. Because corn and soybean are staple food crops for humans, their common use as the main source of dietary energy and protein for food-producing animals directly competes with their allocation for human consumption. Alternatively, de-fatted marine microalgal biomass generated from the potential biofuel production may be a viable replacement of corn and soybean meal due to their high levels of protein, relatively well-balanced amino acid profiles, and rich contents of minerals and vitamins, along with unique bioactive compounds. Although the full-fatted （intact） microalgae represent the main source of omega-3 （n-3） polyunsaturated fatty acids including docohexaenoic acid （DHA） and eicosapentaenoic acid （EPA）, the de-fatted microalgal biomass may still contain good amounts of these components for enriching DHA/EPA in eggs, meats, and milk. This review is written to highlight the necessity and potential of using the de-fatted microalgal biomass as a new generation of animal feed in helping address the globa energy, food, and environmental issues. Nutritional feasibility and limitation of the biomass as the new feed ingredient for simple-stomached species are elaborated. Potential applications of the biomass for generating value-added animal products are also explored.     

5株溶藻抑藻细菌的筛选及果胶酶活性的初步研究

为了解决溶藻细菌分离筛选难的问题,试验以果胶为唯一碳源来分离溶藻菌,然后将分离到的菌株和试验室纯培养的铜绿微囊藻进行溶藻试验,并将溶藻效果与果胶酶活性进行比较分析,探讨细菌溶藻与细菌的果胶酶活性之间的关系。结果发现,分离到的5株细菌均具有较好的溶藻特性,试验第1天就出现菌胶膜包裹微囊藻下沉黄化的想象,5株菌具最佳溶藻效果时的菌液藻液体积比w01>w03=w05>w04>w02;达最佳降解效果的时间w05>w04>w01=w02>w03;持续抑藻时间w04>w05>w01>w02>w03;果胶酶活性w04>w01>w03>w02=w05。以果胶为唯一碳源的培养基可以有效分离到溶藻细菌,但细菌的溶藻效果与果胶酶活性之间无线性关系。     

历史典籍中“藻”及其相关植物的原植物研究

"藻"是现代植物分类体系中的一个单独的大类,现代研究认为藻类植物包含十多个门。对于该类植物的历史,以及中国先民对其认识的历史却知之甚少。为了能够弄清楚这些植物名称对应的原植物,系统搜集整理在历史典籍中记载的与"藻"有关的植物名称及其特征,并利用比较形态学的方法尝试解读。研究发现,在历史典籍中共有9个与"藻"相关的植物名称,研究后确定了7个名称对应的原植物的科学名称。最后解读了中国先民对于"藻"的认识,揭示出"藻"的药用价值与食用价值是中国先民关注这一类植物的主要原因。     

Screening of cultivated seaweeds for antibacterial activity against fish pathogenic bacteria

Because of the evolving resistance of microorganisms to existing antibiotics, there is an increasing need for new antibiotics not only in human but also in veterinary medicine. Competition for space and nutrients led to the evolution of antimicrobial defence strategies in the aquatic environment. Therefore, aquatic organisms, e.g., seaweeds, offer a particularly rich source of potential new drugs. The aim of our studies was to identify seaweeds, which possess activities against fish pathogenic bacteria and could be an alternative to the commonly used antibiotics in aquaculture.Dichloromethane, methanole and water extracts of 26 species of cultivated seaweeds were screened for their antibacterial activities against five fish pathogenic bacteria strains (Aeromonas salmonicida ssp. salmonicida, Aeromonas hydrophila ssp. hydrophila, Pseudomonas anguilliseptica, Vibrio anguillarum, Yersinia ruckeri). The dichloromethane extracts of Asparagopsis armata, Ceramium rubrum, Drachiella minuta, Falkenbergia rufolanosa, Gracilaria cornea and Halopitys incurvus showed strong antibacterial activities. V. anguillarum and P. anguilliseptica were the two most susceptible bacteria strains. The screening results confirm the possible use of seaweeds as a source of antimicrobial compounds or as a health-promoting food for aquaculture.     

藻类在养殖水体中的作用

目前国内外开展了藻类对污水净化的研究.国外利用某些藻类治理水体富营养化的研究取得一定进展[1-2],如日本科学家经过广泛的调查发现水网藻的繁殖能力比形成水华的蓝、绿藻更强,在其生长过程中可以大量吸收水体中的N和P,使N、P含量恢复至正常水平.     

中国海南岛麒麟菜属卡拉胶的制备与性质

本文研究了用海南岛产的三种麒麟菜属海藻制造卡拉胶的方法,以及不同制造方法所得卡拉胶的产率和理化性质。用水提取的卡拉胶产率最高,用碱处理的产率较低。清澜琼枝的卡拉胶产率高达74.6％,耳突麒麟菜和珍珠麒麟菜的产率接近50％。在凝胶强度方面,以用浓NaOH处理的强度最高,耳突麒麟菜和珍珠麒麟菜的凝胶强度高达500g/cm~2左右,琼枝的为350g/cm~2左右。从硫酸基减少和3,6-内醚-半乳糖增加的幅度,以及凝胶强度提高的程度来看,本文浓碱处理法的效果要比国外使用的方法好。试验结果表明海南岛生长的耳突麒麟菜、珍珠麒麟菜和琼枝三者都是制造κ-卡拉胶的很好原料。     

盐田藻类的初步研究

1986～1987年,进行了青岛东风盐场和天津汉沽盐场几个典型的代表性盐池中的藻类资源调查研究。共鉴定出12种藻类,其中10种是徽型藻类,2种是大型藻类。球蓝藻、聚球藻和社氏藻是优势种,周年出现,其最高密度(个细胞/L)分别为10~7～10~8、10~6和10~4～10~5的数量级。而颠藻、四鞭藻、菱形藻、舟形藻、斜纹藻、刚毛藻和根枝藻等数量较少,也不是全年连续分布的。一般说来,这些藻类的多样性与温度呈正相关,而与盐度呈负相关,还讨论了这些藻类在盐池中的生态作用和开发利用的潜力。     

星云湖藻类发展趋势及其资源化利用可行性研究

对星云湖多年表层湖水中藻类的第一手监测资料及大型仿生式除藻船蓝藻控制效果研究资料做了系统的分析研究,旨在揭示星云湖藻类发展趋势,分析藻类资源量,研究藻浆资源化利用。结果表明,星云湖藻类生物量多年呈增长趋势;湖区藻类主要分布于西北湖湾,藻浆量共48 150 m3,鲜重7 704 t,除藻船年平均打捞量共1 684 m3,鲜重269.44 t;星云湖流域藻浆资源化利用具有一定可行性,主要表现为藻浆营养成分明显,无显著生态安全风险,湖区农业生产方式有利于消化利用藻浆,藻浆在星云湖区具有很好的资源化利用前景。     

人工湿地对藻类的去除效果研究

以池塘养鱼废水为进水,引入三级垂直流人工湿地,研究人工湿地对藻类的去除效果。结果表明,人工湿地对藻类总体的去除效果呈现先上升后下降的趋势,7月份人工湿地对藻类的总体去除效果最好,可达到89.61%。湿地对蓝藻的去除率为76.92%-93.77%,对绿藻的去除率为77.50%-89.81%,对硅藻的去除率为83.40%-92.33%,平均去除率分别为86.53%、83.32%和87.53%。这表明湿地对藻类的去除效果为硅藻>蓝藻>绿藻。