Department of Food Science and Technology, Agricultural University of Athens, Athens, Greece.
J Appl Microbiol. 2011 May;110(5):1138-50. doi: 10.1111/j.1365-2672.2011.04961.x. Epub 2011 Feb 23.
In this study, we have investigated the biochemical behaviour of Aspergillus sp. (five strains) and Penicillium expansum (one strain) fungi cultivated on waste cooking olive oil. The production of lipid-rich biomass was the main target of the work. In parallel, the biosynthesis of other extracellular metabolites (organic acids) and enzyme (lipase) and the substrate fatty acid specificity of the strains were studied.
Carbon-limited cultures were performed on waste oil, added in the growth medium at 15g l(-1) , and high biomass quantities were produced (up to c.18g l(-1) , conversion yield of c. 1·0 g of dry biomass formed per g of fat consumed or higher). Cellular lipids were accumulated in notable quantities in almost all cultures. Aspergillus sp. ATHUM 3482 accumulated lipid up to 64·0% (w/w) in dry fungal mass. In parallel, extracellular lipase activity was quantified, and it was revealed to be strain and fermentation time dependent, with a maximum quantity of 645 U ml(-1) being obtained by Aspergillus niger NRRL 363. Storage lipid content significantly decreased at the stationary growth phase. Some differences in the fatty acid composition of both cellular and residual lipids when compared with the initial substrate fat used were observed; in various cases, cellular lipids more saturated and enriched with arachidic acid were produced. Aspergillus strains produced oxalic acid up to 5·0 g l(-1) .
Aspergillus and Penicillium strains are able to convert waste cooking olive oil into high-added-value products.
Increasing fatty wastes amounts are annually produced. The current study provided an alternative way of biovalourization of these materials, by using them as substrates, to produce added-value compounds.
本研究调查了在废烹饪橄榄油上培养的曲霉属（5 株）和扩展青霉（1 株）真菌的生化行为。主要目标是生产富含脂质的生物质。同时，研究了菌株的其他胞外代谢物（有机酸）和酶（脂肪酶）的生物合成以及底物脂肪酸特异性。
在生长培养基中添加 15g l(-1) 的废油进行碳限制培养，可生产出大量的生物质（高达约 18g l(-1)，每消耗 1g 脂肪可转化生成约 1.0g 的干生物质，转化率更高）。几乎所有培养物中都积累了大量的细胞脂质。曲霉属 ATHUM 3482 在干燥真菌质量中积累了高达 64.0%（w/w）的脂质。同时，测定了细胞外脂肪酶的活性，发现其与菌株和发酵时间有关，黑曲霉 NRRL 363 获得的最大量为 645U ml(-1)。在静止生长阶段，储存脂质含量显著降低。与初始底物脂肪相比，观察到细胞和残留脂质的脂肪酸组成存在一些差异；在各种情况下，产生了更饱和且富含花生酸的细胞脂质。曲霉属菌株可产生高达 5.0g l(-1)的草酸。
曲霉属和青霉属菌株能够将废烹饪橄榄油转化为高附加值产品。
每年都会产生越来越多的脂肪废物。本研究提供了一种生物增值这些材料的替代方法，即将它们用作底物来生产附加值化合物。
