Arriaga Sonia, Revah Sergio
Universidad Autónoma Metropolitana-Iztapalapa, Laboratorio de Bioprocesos, Departamento de Ingeniería de Procesos e Hidráulica, Av. San Rafael Atlíxco No. 186, Col. Vicentina, C.P. 09340, Mexico, Distrito Federal.
Biotechnol Bioeng. 2005 Apr 5;90(1):107-15. doi: 10.1002/bit.20424.
The removal of hydrophobic pollutants in biofilters is often limited by gas liquid mass transfer to the biotic aqueous phase where biodegradation occurs. It has been proposed that the use of fungi may improve their removal efficiency. To confirm this, the uptake of hexane vapors was investigated in 2.6-L perlite-packed biofilters, inoculated with a mixed culture containing bacteria and fungi, which were operated under neutral or acid conditions. For a hexane inlet load of around 140 g.m-3.h-1, elimination capacities (EC) of 60 and 100 g.m-3.h-1 were respectively reached with the neutral and acid systems. Increasing the inlet hexane load showed that the maximum EC obtained in the acid biofilter (150 g.m-3.h-1) was twice greater than in the neutral filter. The addition of bacterial inhibitors had no significant effect on EC in the acid system. The biomass in the acid biofilter was 187 mg.g-1 (dry perlite) without an important pressure drop (26.5 mm of water.m-1reactor). The greater efficiency obtained with the acid biofilter can be related to the hydrophobic aerial hyphae which are in direct contact with the gas and can absorb the hydrophobic compounds faster than the flat bacterial biofilms. Two fungi were isolated from the acid biofilter and were identified as Cladosporium and Fusarium spp. Hexane EC of 40 g.m-3.h-1 for Cladosporium sp. and 50 g.m-3.h-1 for Fusarium sp. were obtained in short time experiments in small biofilters (0.230 L). A biomass content around 30 mg.g-1 (dry perlite) showed the potential for hexane biofiltration of the strains.
生物滤池中疏水性污染物的去除通常受限于气液传质至发生生物降解的生物水相。有人提出使用真菌可能会提高其去除效率。为证实这一点，在接种了含细菌和真菌的混合培养物的2.6升珍珠岩填充生物滤池中研究了己烷蒸气的吸收情况，该生物滤池在中性或酸性条件下运行。对于约140 g·m⁻³·h⁻¹的己烷进口负荷，中性和酸性系统的去除能力（EC）分别达到60和100 g·m⁻³·h⁻¹。增加进口己烷负荷表明，酸性生物滤池中获得的最大EC（150 g·m⁻³·h⁻¹）是中性滤池的两倍。添加细菌抑制剂对酸性系统中的EC没有显著影响。酸性生物滤池中的生物量为187 mg·g⁻¹（干珍珠岩），且没有明显的压降（26.5毫米水柱·m⁻¹反应器）。酸性生物滤池获得的更高效率可能与疏水性气生菌丝有关，这些菌丝与气体直接接触，能够比扁平的细菌生物膜更快地吸收疏水性化合物。从酸性生物滤池中分离出两种真菌，鉴定为枝孢属和镰刀菌属。在小型生物滤池（0.230升）的短期实验中，枝孢属的己烷EC为40 g·m⁻³·h⁻¹，镰刀菌属的为50 g·m⁻³·h⁻¹。约30 mg·g⁻¹（干珍珠岩）的生物量含量表明这些菌株具有己烷生物过滤的潜力。
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