REMERCIEMENTS Nous remercions le CRSBAN (UEMOA) et le CIOSPB pour leur appui financier dans la conduite des travaux de recherche. RESUMELa gestion des déchets municipaux est devenue une préoccupation majeure dans les pays en développement, due au manque de politique et de stratégie adaptées. L'étude réalisée a porté sur la valorisation biotechnologique de la fraction biodégradable des déchets au Burkina Faso. Une analyse physico-chimique des déchets échantillonnés dans trois (3) centres de précollecte de déchets municipaux de Ouagadougou a été réalisée. L'influence du type d'inoculum (eaux usées, bouse bovine, flux de broyat de termites et une mixture de ces 3 inocula) et de la charge en substrat (déchets organiques) a été évaluée au cours d'essais de fermentation méthanique. Les résultats obtenus ont montré que les déchets organiques municipaux constituent un substrat de prédilection pour la méthanisation avec un ratio C/N de 31,65. Les essais de fermentation ont permis de noter que la bouse bovine comme inoculum avec une charge en déchets municipaux de 2% donnait la meilleure production de biométhane (297,65 l CH 4 / Kg MSV). Il ressort de cette étude que les déchets municipaux peuvent être traités par la voie de la biométhanisation car présentant un potentiel de bioconversion intéressant. © 2015 International Formulae Group. All rights reserved.Mots clés : Déchets organiques, digestion anaérobie, biométhane, environnement, Burkina Faso. Optimization of biomethane production from municipal solid organic wastes ABSTRACTMunicipal solid organic wastes management became a major preoccupation. The achieved study focuses the biotechnological valorization of the biodegradable fraction of solid organic wastes in Burkina Faso.M. NIKIEMA et al. / Int. J. Biol. Chem. Sci. 9(5): 2743-2756, 2015 2744 Physicochemical characterization analysis of solid wastes sampled in 03 Ouagadougou's centers of municipal wastes deposits was achieved. The influence of inoculum source (wastewater, bovine dung, termites' homogenate and mixture) and substrate concentration (municipal solid waste) were evaluated during biomethane production tests. Results showed that organic fraction of solid wastes represent a source of predilection for methanization with 31.65 C/N cow. Fermentation tests showed that bovine dung used as inoculum in 2% of municipal solid waste gave the highest rate of biomethane production (297.65 l CH 4 / Kg vs). The results demonstrate that municipal wastes can be valorized by biomethanization way because presenting interesting bioconversion potential.

Lubricants are very often found in nature under waste-oil forms and represent for the environment a real danger of pollution due to the difficulty of their biodegradation. The situation is especially worrying in most developing countries in particular those of Sub-Saharan Africa due to the absence of regulation or control. The present work aims to isolate bacterial strains able to degrade hydrocarbons which can later be used in biotechnology for environments depollution. Oil-contaminated wastewater samples were collected in Ouagadougou city (Burkina Faso) and then used as source of bacterial isolation. Appropriate amounts of samples were inoculated to a mineral salt medium (MS) with Total Quartz 9000 oil as sole carbon and energy source and then incubated for enrichment, prior to microbe isolation. Two bacterial strains namely S2 and S 7 were isolated from the enrichment cultures. The strains were tested for their ability to degrade other hydrocarbons (i.e. gasoline, diesel oil, brake oil) and for temperature, pH and salt concentration ranges for growth before their biochemical characteristics were defined. Based on their morphological, physiological and biochemical traits, strains S 2 and S 7 belong to Acinetobacter and Pseudomonas genera, respectively.

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A novel methane-oxidizing bacterial strain SS37A-ReT was isolated from surface soil of a rice paddy field in Japan. Cells were Gram-stain-negative, motile rods with single polar flagellum and type II intracytoplasmic membrane arrangement. The strain grew on methane or methanol as the sole carbon and energy source. It grew at 15–37 °C (optimum 25–30 °C), pH 6.0–9.0 (optimum 7.0–8.0) and with 0–0.1 % (w/w) NaCl (no growth at 0.5 % or above). Cells formed cysts, but not exospores. The results of sequence analysis of the 16S rRNA gene indicated that SS37A-ReT represented a member of the family Methylocystaceae , with the highest similarity (98.9 %) to Methylocystis parva corrig. OBBPT. Phylogenetic analysis of pmoA and mxaF genes and core genes in the genome indicated that the strain was closely related to the members of the genus Methylocystis , while the analysis of the mmoX gene indicated the close relationships with the genus Methylosinus . The values of genome relatedness between SS37A-ReT and species of the genera Methylocystis and Methylosinus were 78.6–82.5% and 21.7–24.9 % estimated by the average nucleotide identity and digital DNA–DNA hybridisation, respectively, showing the highest values with Methylocystis echinoides LMG 27198T. The DNA G+C content was 63.2 mol% (genome). The major quinone and fatty acids were Q-8 and, C18 : 1 (C18 : 1ω8t and C18 : 1ω8c) and C18 : 2, respectively. On the basis of the phenotypic and phylogenetic features, the strain represents a novel species of the genus Methylocystis , for which the name Methylocystis iwaonis sp. nov. is proposed. The type strain is SS37A-ReT (=JCM 34278T =NBRC 114996T=KCTC 82710T).