西双版纳亚洲象的现状

1995至1997年在云南西双版纳保护区对亚洲象数号和分布的调查,发现西双版纳现有大象170～200头,分属于17～19个群体,群体平均大小为1O（2～27）头.勐养和尚勇地区已形成2个相互隔离的种群,分布区从整体看有退缩的趋势,已基本限于保护区范围之内

Biodiesel-Oriented Microbial Lipid Research

Biodiesel is a mixture of long-chain fatty acid methyl esters. It was made from vegetable oil and fats, and is renewable with outstanding combustion profile. It will be beneficial to meet ever-growing energy demanding if biodiesel is widely applied. On the other hand, carbohydrates, either from starchy material or lignocellulosic biomass, are the most abundant renewable resources. In this context, it is pivotal to convert carbohydrates into products with similar properties to conventional fossil fuel. Some microorganisms can accumulate lipid to more than 20 wt% of their biomass when carbohydrates or related carbon sources are metabolized. Microbial lipid, especially produced by yeasts, consists mainly of triacylglycerides with fatty acid compositional profile similar to those of the commercial vegetable oils. Because it can be obtained from renewable raw materials, and be produced continuously with no extensive arable land requirement, microbial lipid has been considered as potential feedstock for biodiesel industry and an important topic for industrial biotechnology. Microbial lipid production is an aerobic biochemical process that generates intracellular lipid using organic substrates. During the past few years, we have advocated the proposal of Biomass-to-Biodiesel that produces biodiesel using lignocellulosic materials. This proposal included three steps, 1) Hydrolysis of lignocellulose to carbohydrates; 2) Lipid production with oleaginous microorganisms; and 3) Transesterification of microbial lipid to biodiesel. We identified a hand of outstanding oleaginous yeasts, including Rhodosporidium toruloides, Lipomyces starkeyi, and Cryptococcus curvatus. These yeasts produced microbial lipid using materials including glucose, xylose, N-acetylglucosamine, raw glycerol, corn stalk hydrolysates and Jerusalem artichoke juice. We optimized lipid production processes. When using the yeast R. toruloides Y4 as the lipid producer in a 15-L bioreactor, we achieved lipid content, production titer and lipid productivity of over 65 wt%, 100 g/L and 0.8 g/l/h, respectively. We also demonstrated that biodiesel can be produced using either oleaginous microbial biomass or microbial lipid as the feedstock. Taken together, we will report the most recent progresses in biodiesel-oriented microbial lipid research in Dalian Institute of Chemical Physics, Chinese Academy of Sciences

转化N-乙酰-D-葡糖胺产油真菌的筛选

对21株真菌利用甲壳素解聚产物N-乙酰-D-葡糖胺（NAG）为碳源积累油脂的能力进行了筛选。碳源同化实验得到可同化NAG的真菌7株，进一步筛选出能利用NAG积累油脂的酵母3株。摇瓶实验表明，C．albidus ATCC 56298和T.fermentans CICC1368利用NAG发酵菌体油脂含量可分别达到67％和48％。气相色谱分析表明菌油富含棕榈酸、硬脂酸和油酸，与常规植物油脂的脂肪酸组成相似。研究结果拓宽了微生物油脂发酵的原料