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High-density culture for microbial lipid preparation from low-cost lignocellulosic feedstocks is crucial for commercial-scale biodiesel production. Herein, fed-batch saccharification of alkaline organosolv pretreatment (AOP) of corn stover at an extremely high solids content of 47% (w/v) released 299.5 g/L of lignocellulosic sugars including 18.3% of soluble oligosaccharides. Three types of liquid hydrolysates for seed culture, fermentation, and feeding during fed-batch culture were obtained from the hydrolysate slurry using a two-step washing strategy with 99.3% of sugars recovery. Cutaneotrichosporon oleaginosum showed excellent capacity for assimilating both monosaccharides and oligosaccharides for lipid production using the fed-batch culture mode. Lipid concentration, content, and yield gained 42.3 g/L, 64.6%, and 20.4 g/100 g, respectively. Turbid hydrolysate collected with high recovery of high-concentration sugars and simplified process could be directly served as feeding medium. In general, the overall hydrolysis yield and lipid yield using fed-batch mode accounted for 93.2% and 97.6% of those using batch mode, respectively, resulting in a lipid output of 102.8 g/kg raw corn stover. The fatty acid composition and the prediction of biodiesel properties of lipid samples indicated the suitability for high-quality fuel production. This study provided valuable information for designing highly efficient lignocelluloses-to-biodiesel routes. [ABSTRACT FROM AUTHOR]

With the continuing consumption of resources and increasingly prominent environmental issues, microalgal resource utilization has received extensive attention. In this study, based on the microalgal investigation in desert biological soil crusts (BSCs) using pyrosequencing technology, the cultivated crust microalgae were further isolated in order to obtain high quality microalgae for resource utilization. The results showed that with crust development and succession, microalgal diversity gradually decreased, including the number of operational taxonomic units (OTUs) and genus, although Microcoleus always was the dominant genera. Pyrosequencing obtained 630 OTUs of cyanobacteria, 25 OTUs of green algae and 9 OTUs of diatom; however, part of cultivated microalgae still could not yet be detected due to the DNA extraction preferences and errors caused by PCR amplification. After isolation, four strains were purified and cultivated, including two filamentous cyanobacteria Microcoleus vaginatus BSC-06 and Scytonema javanicum BSC-39, and two unicellular green algae Chlorella sp. BSC-24 and Monoraphidium dybowskii BSC-81. The two green algae grew fast (>250 mg L -1  d -1 ), and achieved high lipid productivity up to 75–85 mg L -1  d -1 , with lipid content of 28.7–39.0%, thus was considered as promising feedstock for biodiesel production. In addition, the two crust cyanobacteria could be used to construct artificial cyanobacterial soil crusts in desertification control, although their biomass accumulation was not as high as that in the green algae. Ultimately, combining biodiesel production with desertification control would not only improve desert environments, but also provide ideal places for the local microalgal resource exploitation, further promoting desert socioeconomic development. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify the most promising species as biodiesel feedstock for large-scale cultivation in north China. Eight species of microalgae, selected on the basis of indoor screening, were tested for lipid productivity and the suitability of their fatty acid profiles for biodiesel production under outdoor conditions. Among them, three species Desmodesmus sp. NMX451, Desmodesmus sp. T28-1 and Scenedesmus obtusus XJ-15 were selected for further characterization due to their possessing higher lipid productivities and favorable biodiesel properties. The best strain was S. obtusus XJ-15, with highest biomass productivity of 20.2 g m −2 d −1 and highest lipid content of 31.7% in a culture of 140 L. S. obtusus XJ-15 was further identified as the best candidate for liquid biofuel production, characterized by average areal growth rate of 23.8 g m −2 d −1 and stable lipid content of above 31.0% under a scale of 1400 L over a season. [ABSTRACT FROM AUTHOR]