Duarte E A A, Lacerda G V, de Oliveira T A S, Brendel M, Loguercio L L, Cascardo J C
Centro de Biotecnologia e Genética, Universidade Estadual de Santa Cruz, Ilhéus, BA, Brasil.
Genet Mol Res. 2013 Oct 10;12(4):4422-33. doi: 10.4238/2013.October.10.8.
The increasing world production of biodiesel has resulted in an accumulation of crude glycerol as the major byproduct. This could be used as carbon source for industrial microbiology, with economic and environmental advantages for the biodiesel industry. We explored an Atlantic Rainforest soil sample to search for crude glycerol-degrading microorganisms. Microcosms of this soil were established containing minimal medium + 8% crude glycerol (w/w); the biological activity was measured by respirometry. High CO2 levels were found in some of the crude glycerol microcosms, suggesting the activity of microorganisms capable of degrading this residue. In an attempt to isolate and cultivate these microorganisms in vitro, aliquots of the soil suspension were plated on minimal medium containing 10% crude glycerol (v/v). Out of 19 morphologically distinct isolates, 12 bacteria and 6 yeasts were identified by PCR from universal primers 16S and 26S rDNA, respectively. Optical density readings revealed growth differences among cultures. Two yeasts and three bacteria with distinct growth profiles stood out and appeared to have potential for liquid fermentation of crude glycerol. The yeasts adapted rapidly, but produced relatively little biomass. Opposite tendencies were found in the bacteria. Amplicon sequencing placed the bacterial isolates as close to Staphylococcus arlettae, Pseudomonas citronellolis, and Bacillus megaterium, and the yeasts to Trichosporon moniliiforme and Meyerozyma guilliermondii. We concluded that these species have potential for use in crude glycerol bioreactors and for bioremediation processes.
全球生物柴油产量的不断增加导致了作为主要副产物的粗甘油的积累。这可以用作工业微生物学的碳源，对生物柴油行业具有经济和环境优势。我们探索了一份大西洋雨林土壤样本，以寻找能降解粗甘油的微生物。建立了这种土壤的微观世界，其中含有基本培养基 + 8% 的粗甘油（w/w）；通过呼吸测定法测量生物活性。在一些粗甘油微观世界中发现了高二氧化碳水平，这表明存在能够降解这种残留物的微生物的活性。为了在体外分离和培养这些微生物，将土壤悬浮液的等分试样接种在含有10% 粗甘油（v/v）的基本培养基上。在19个形态不同的分离物中，分别通过通用引物16S和26S rDNA的PCR鉴定出12种细菌和6种酵母。光密度读数揭示了不同培养物之间的生长差异。两种酵母和三种具有不同生长曲线的细菌脱颖而出，似乎具有粗甘油液体发酵的潜力。酵母适应迅速，但产生的生物量相对较少。在细菌中发现了相反的趋势。扩增子测序将细菌分离物定位为与阿氏葡萄球菌、香茅假单胞菌和巨大芽孢杆菌相近，而酵母则与念珠状丝孢酵母和季也蒙毕赤酵母相近。我们得出结论，这些物种具有用于粗甘油生物反应器和生物修复过程的潜力。
