PAH removal by immobilized bacterial cells-support systems using low-cost culture media for biomass production

The use of immobilized biomass for polycyclic aromatic hydrocarbon (PAH) removal from a liquid phase is a very promising technology. For this technology to be economically viable, the biomass production and immobilization should be as cost-effective as possible. The aim of this work was to produce a low-cost PAH removal system consisting of an immobilized biomass on different supports. A co-culture formed by two PAH-degrading bacteria (Pseudomonas monteilii P26 and Gordonia sp. H19, autochthonous Patagonian strains) was used. Industrial by-products such as sugar cane molasses, corn steep liquor, whey permeate and crude glycerol were used in combination to formulate different low-cost growth media. Naphthalene, phenanthrene and pyrene removal was evaluated using immobilized bacteria in polyurethane foam cubes, in sand and in calcium alginate beads. The growth of P. monteilii P26 and Gordonia sp. H19 was satisfactory in the different media assayed. The culture medium containing 1% corn steep liquor-2% molasses was selected for biomass production for subsequent immobilization. The removal of PAHs in different immobilization systems could be attributed to both the supports and the bacteria (up to 88.9% pyrene removal in 12 days); thus, immobilized cell systems for removing PAHs from an aqueous phase are proposed.