木质纤维素是地球上最丰富的能够转化成生物燃料的可再生资源。然而，由于木质纤维素的抗降解屏障，当前生物燃料产品单一，成本高昂等因素严重阻碍了其产业化进程。为了解决这一问题，本研究通过将纤维素的厌氧微生物降解糖化及含油微生物发酵产油过程串联耦合，开发一种新的工艺过程，以木质纤维素为原料，生产单细胞油脂，可用于生产生物柴油及高附加值副产品，从而为规模化原料提供、具有整体经济竞争力的木质纤维素基生物能源产业化奠定基础。本研究具体结果如下：

1.低成本的木质纤维素预处理方法开发；为了有效克服木质纤维素的抗降解屏障，本研究开发了一种能够破坏木质素结构并增加纤维素比表面积的混碱预处理方法，通过优化处理温度、混碱比例、反应时间等预处理参数，最终确定了最优预处理条件：氢氧化钠1% (w/w)，氢氧化钙7% (w/w)，固液比1：10，100℃处理4h。

2. 高含油微生物的筛选；从浙江、广东、云南、福建、海南等代表性生境中采样，利用松树花粉富集，结合复合抗生素筛选平板筛选得到高含油微生物（油脂含量>35%干重）32株，其中包括酵母3株，破囊壶菌科的真菌29株，对代表性菌株进行了鉴定及基本生理生化研究。

Lignocellulose is the most abundant renewable material which can be transformed into bioenergy. However, recalcitrance of the lignocellulose, the narrow varieties and the low price of downstream biofuel products had seriously restrained the industrialization of biofuels. To tackle this problem, this study couples an anaerobic bacteria which is used for cellulose saccharification with an oleaginous microorganism which is responsible to produce oil from the sugars. A new process is then constructed where lignocellulosic biomass is transformed into single cell oils, which can be used to produce biodiesel and high value-added product. The detailed results of this study are summarized as follows:

1. The development of low cost lignocellulose pretreatment: In order to overcome recalcitrance of the lignocellulose, a mixed alkali lignocellulose pretreatment technique which is able to isolate lignin and increase the enzymatic accessibility of cellulose was investigated. After optimizing the temperature, amount of alkali and reaction time, the final method is determined as adding 1%(w/w) sodium hydroxide, 7% calcium hydroxide and ten times water of the material before maintained at 100°C for 4 hours.

2. Screening microbial containing high level of lipids: Including 3 yeasts and 29 Traustochytriaceaes, 32 high lipids contained microbial was isolated from samples which were collected from typical biotic environment of Zhejiang, Guangdong, Yunnan, Fujian and Hainan Province with pine pollen enrichment and medium containing compound antibiotics. After strain identification, basic physiological and biochemical properties of the typical strains were investigated.