International Biodeterioration & Biodegradation 60 (2007) 35–39 Solid culture amended with small amounts of raw coffee beans for the removal of petroleum hydrocarbon from weathered contaminated soil Adriana Rolda´ n-Martı´n a , Graciano Calva-Calva a , Norma Rojas-Avelizapa b , Ma. Dolores Dı´az-Cervantes a , Refugio Rodrı´guez-Va´zquez a,Ã a Departamento de Biotecnologı´a y Bioingenierı´a, Centro de Investigacio´n y Estudios Avanzados del IPN, Av . IPN 2508 Col. San Pedro Zacatenco C.P. 03760 Me´xico D.F., Mexico b Biotecnologı´a del petro´leo, Instituto Mexicano del Petro´leo, Mexico Received 16 March 2006; accepted 26 October 2006 Available online 7 March 2007 Abstract Solid culture with small amounts of low-quality raw coffee beans was used for total petroleum hydrocarbon (TPH) removal from a weathered and polluted soil. Soil contaminated with 58 000 mg kg 1 of TPH was treated with soil:coffee bean ratios of 98:2, 96:4, 94:6, and 92:8, at a C:N:P ratio of 100:10:1, 20% humidity, and 28 1C, for periods of 15, 60, and 90 days. The highest TPH removal (63%) was obtained with a soil/bean ratio of 98:2 over 15 days, corresponding with the highest rates of microbial respiration and the greatest increases in bacterial and fungal counts to 9 lnCFU and 6 lnCFU, respectively. Scanning electron microscopy showed high fungal colonization of coffee beans, with Mucor sp., Aspergillus sp., Aspergillus niger., and Penicillium sp. growing on TPH as sole carbon source. r 2006 Published by Elsevier Ltd. Keywords: Bioremediation; Coffee bean; Nutrients; Solid culture; Total petroleum hydrocarbons 1. Introduction Several studies have reported bioremediation of con- taminated soils by adding high quantities of agro-industrial wastes (composting) such as chopped wheat straw and pine wood chips (Sample et al., 2001). When high amounts of agro-industrial residues are added, soil apparent bulk density, porosity, and oxygen diffusion increase. Agro- industrial wastes can also be used for fungal growth (Rodrı´guez-Va´zquez et al., 1999), as these residues contain nutrients and are generally rich in phosphorus, nitrogen, and carbohydrates (Pandey et al., 2000), which are potentially important for the growth of organic pollutant degraders. Several igninolytic fungi have been grown on sugarcane and used as inoculum for the bioremediation of soil contaminated with polychlorinated biphenyls (Ferna´ n- dez-Sa´nchez et al., 2001), phenanthrene (Cha´vez-Go´ mez et al., 2003), and benzo(a)pyrene (Dzul-Puc et al., 2004); such lignocellulosic materials are the natural habitat of the fungi. Previous work (Dzul-Puc et al., 2004) has reported that the filamentous fungus, Penicillium frequentans, isolated from hydrocarbon contaminated soils, grown on sugarcane, and added to a soil spiked with 200 ppm phenanthrene, achieved 74% removal of the pollutant from the soil after 7 days, while a mixed culture of P. frequentans and Pseudomonas pickettii achieved 73.6% removal at 18 days. Other studies have demonstrated microbial biostimulation in a soil/sugarcane bagasse 85:15 system, with removal of 74% of total petroleum hydro- carbons (TPH) from the soil at 16 days (Pe´ rez-Armenda´ riz et al., 2004). Even though several materials have been utilized for soil treatment, mainly under composting conditions (Sample et al., 2001), and at low amounts (Ferna´ndez-Sa´nchez et al., 2001; Cha´vez-Go´mez et al., 2003; Dzul-Puc et al., 2004; Pe´rez-Armenda´ riz et al., 2004), there are thousands of other agricultural materials that could be utilized, such as low-quality coffee beans, which in ARTICLE IN PRESS www.elsevier.com/locate/ibiod 0964-8305/$ - see front matter r 2006 Published by Elsevier Ltd. doi:10.1016/j.ibiod.2006.10.008 Ã Corresponding author. Fax: +55 5061 3313. E-mail address: rrodrig@mail.cinvestav.mx (R. Rodrı´guez-Va´ zquez).