title: Co-composting of spent coffee ground with olive mill wastewater sludge and poultry manure and effect of Trametes versicolor inoculation on the compost maturity.
abstract: The co-composting of spent coffee grounds, olive mill wastewater sludge and poultry manure was investigated on a semi-industrial scale. In order to reduce the toxicity of the phenolic fraction and to improve the degree of composting humification, composts were inoculated with the white-rot fungus Trametes versicolor in the early stages of the maturation phase. During composting, a range of physico-chemical parameters (temperature and both organic matter and C/N reduction), total organic carbon, total nitrogen, elemental composition, lignin degradation and spectroscopic characteristics of the humic acids (HAs) were determined; impacts of the composting process on germination index of Hordeum vulgare and Lactuca sativa were assessed. The coffee waste proved to be a highly compostable feedstock, resulting in mature final compost with a germination index of 120% in less than 5 months composting. In addition, inoculation with T. versicolor led to a greater degree of aromatization of HA than in the control pile. Moreover, in the inoculated mixture, lignin degradation was three times greater and HA increased by 30% (P<0.05), compared to the control pile. In the T. versicolor inoculated mixture, the averages of C and N were significantly enhanced in the HA molecules (P<0.05), by 26% and 22%, respectively. This improvement in the degree of humification was confirmed by the ratio of optical densities of HA solutions at 465 and 665 nm which was lower for HA from the treated mixture (4.5) than that from the control pile (5.4).
authors.affiliation: Université de Sfax, Ecole Nationale d'Ingénieurs de Sfax, Laboratoire de Génie enzymatique et Microbiologie, BP 1173, 3038 Sfax, Tunisia. ridha.hachicha@yahoo.com
authors.forename: Ridha
authors.initials: R
authors.lastname: Hachicha
authors.forename: Olfa
authors.initials: O
authors.lastname: Rekik
authors.forename: Salma
authors.initials: S
authors.lastname: Hachicha
authors.forename: Mounir
authors.initials: M
authors.lastname: Ferchichi
authors.forename: Steve
authors.initials: S
authors.lastname: Woodward
authors.forename: Nasri
authors.initials: N
authors.lastname: Moncef
authors.forename: Juan
authors.initials: J
authors.lastname: Cegarra
authors.forename: Tahar
authors.initials: T
authors.lastname: Mechichi
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D002244:Carbon / Q000737:chemistry; D003069:Coffee / Q000737:chemistry*; D001467:Hordeum / Q000187:drug effects / Q000254:growth & development; D006812:Humic Substances / Q000032:analysis; D007220:Industrial Waste; D018545:Lactuca / Q000187:drug effects / Q000254:growth & development; D008031:Lignin / Q000032:analysis; D008372:Manure / Q000382:microbiology*; D009584:Nitrogen / Q000737:chemistry; D000069463:Olive Oil; D010938:Plant Oils / Q000302:isolation & purification; D059808:Polyphenols / Q000032:analysis; D011200:Poultry; D012722:Sewage / Q000382:microbiology*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D013696:Temperature; D055454:Trametes / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D003069:Coffee; D006812:Humic Substances; D007220:Industrial Waste; D008372:Manure; D000069463:Olive Oil; D010938:Plant Oils; D059808:Polyphenols; D012722:Sewage; D012987:Soil; D002244:Carbon; D008031:Lignin; D009584:Nitrogen