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The high phenolic content of Palm Oil Mill Effluent (POME) constitutes an environmental concern. In this study, laccase producing microorganisms were isolated from POME samples collected in Cote d’Ivoire for their possible use in POME treatment. Strain showing the highest laccase activity was identified by ITS1-5.8S-ITS2 region sequencing as Trametes polyzona. A maximum laccase production (156.3 U/mL) was obtained after 10 days of incubation under shaking condition, at 37 °C, pH 4, with starch (1%), tryptone (0.3%) and 10 mM of guaiacol. The partially purified laccase of 31 kDa exhibited maximum activity at 50 °C and pH 4.5 with a Km for guaiacol and Vmax of 0.7 mM and 0.04 mM/min, respectively. Metals, SDS and EDTA did not inhibit his activity. Used as biotreatment agent, T. polyzona MPS1-3 reduced COD, total suspended solids, total solids and total phenolics by 16.03%, 70.15%, 38.9%, 50.84%, respectively, for sterilized POME and by 13.09%, 58.07%, 36.53%, 42.05% for unsterilized POME. These results showed the promising application of T. polyzona for bioremediation of phenolics compounds in wastewater and it potentially useful in several other biotechnological applications.

Palm wine, the most commonly consumed traditional alcoholic beverage in Western Africa, harbours a complex microbiota and metabolites, which plays a crucial role in the overall quality and value of the product. In the present study, a combined metagenomic and metabolomic approach was applied to describe the microbial community structure and metabolites profile of fermented saps from three palm species (Elaeis guineensis, Raphia hookeri, Borassus aethiopum) in Côte d’Ivoire. Lactobacillaceae (47%), Leuconostocaceae (16%) and Acetobacteriaceae (28%) were the most abundant bacteria and Saccharomyces cerevisiae (87%) the predominant yeasts in these beverages. The microbial community structure of Raphia wine was distinctly different from the others. Multivariate analysis based on the metabolites profile clearly separated the three palm wine types. The main differentiating metabolites were putatively identified as gevotroline hydrochloride, sesartemin and methylisocitrate in Elaeis wine; derivative of homoserine, mitoxantrone in Raphia wine; pyrimidine nucleotide sugars (UDP-D-galacturonate) and myo-Inositol derivatives in Borassus wine. The enriched presence of gevotroline (an antipsychotic agent) and mitoxantrone (an anticancer drug) in palm wine supports its therapeutic potential. This work provides a valuable insight into the microbiology and biochemistry of palm wines and a rationale for selecting functional microorganisms for potential biotechnology applications.

The potential of medium chain fatty acids (MCFA) production from two seasonal leachates along with their bacterial community structure were investigated using GC-FID and Illumina high-throughput sequencing during the acid chain elongation process. Significant amounts of MCFA (C6-10) were produced during the experiment, especially with rainy season leachate. The amounts ranged from 1646 mg/l to 22,000 mg/l for C6-C8 and reached 959.65 mg/l for C9 and C10, with optimum values obtained on day 21. Bacterial communities were also different among seasonal samples, with Bacteroidetes, Firmicutes, and Proteobacteria being the most abundant phyla. The relative abundance of Lactobacillus, Clostridium, and Pseudomonas increased during fermentation and showed positive correlations with MCFA with longer chains (C6-C10), demonstrating their probable involvement in the chain elongation process. This study enhances our understanding of the composition, structure and contribution of the bacterial community during the chain elongation process and gives value to leachate from solid waste in sub-Saharan countries.

Despite the increasing importance of palm wines as a key element in Ivorian socio-cultural practices, and the high involment of yeasts in the production of these beverages, no studies have been devoted to aroma production of yeasts and their potential uses in biotechnological applications. In this work, aroma profiles of 20 non pathogenic yeast strains (11 from raffia and 9 from ron, representing 13 species) among the 21 yeasts isolated were established using HS–SPME–GC/MS analysis. A total of 50 Volatile Organic Compounds (VOCs) produced by these yeasts were identified and grouped into five main families, namely higher alcohols, aldehydes, ketones, organic acids and esters. Among these VOCs, esters were the most abundant (28 compounds). Some strains produced specific compounds of technological interest which could be used for diverse applications, such as beverages, ice creams, baked goods and desserts and synthetic flavouring ingredient. Among them, Hanseniaspora jakobsenii CLIB 3083 produced the highest number of VOCs.

In order to assess the genetic diversity and population structure of indigenous S. cerevisiae from Côte d'Ivoire, a total of 170 strains were isolated from four traditional alcoholic beverages through nine regions. Microsatellite analysis performed at 12 loci revealed that strains of palm oil and raffia wine were genetically related, unlike those of tchapalo and ron wine which formed two s from palm oil wine and raffia wine were clearly inbred. In comparison with the European, North American, Asian and others West African populations, Ivorian population was well defined, although most of these strains were admixed. Among these strains, only isolates from raffia wine appeared to have alleles in common to all populations.

The aims of this study were to investigate the food safety knowledge and practices of food handlers and to assess the sanitary conditions of attieke production units in the South of C?te d’Ivoire. A cross-sectional study was conducted during 4 months in 2012 in 7 localities and data were collected using questionnaire and observation checklist and microbiological analysis of hands. A total of 775 attieke production units were involved in this survey. Seventy-one percent (71%) were located on public domains and only 70 production units (9%) used septic tank as a mean of final deposal for liquid waste. Hygiene conditions and practices of food handlers in attieke production units were inadequate. The presence of specific microorganisms such as Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter agglomerans, Citrobacter youngae, Klebsiella oxytoca and Citrobacter freundi was indicative of a degree of ignorance on the part of food handlers towards proper hygienic practices.

Two lactic acid bacteria strains (At1BEAE22 and At344E21) isolated during tchapalo production were identified on the basis of phenotypic analyses. Bacteriocins produced by these strains were tested for their antimicrobial activities using well diffusion agar method. Heat resistance, pH sensitivity and enzyme treatments were also analyzed. Results showed that both lactic acid bacteria strains were identified as Pediococcus acidilactici. Their bacteriocins inhibited growth of Lactobacillus delbrueckii F/31, Listeria innocua ATCC 33090, Enterococcus faecalis, Enterococcus faecalis ATCC 29212, Streptococcus sp, Enterococcus faecalis CIP 105042 and Enterococcus faecium ATCC 51558. These bacteriocins were heat stable at 60&degC for 30 min for all indicator bacteria. However, they remained active only against Lactobacillus delbrueckii and Listeria innocua at 121&degC for 60 min. Moreover, they were active in a wide range of pH (3 to 9) with a maximum activity observed at pH 5 and 6 on all indicator bacteria. But, bacteriocin from Pediococcus acidilactici At34E21 was more stable at acidic pH than basic one. The fact that the bacteriocin was inactivated by proteinase K and α-chymotrypsin indicated its proteinaceous nature, a general characteristics of bacteriocins.

The production of tchapalo remains more or less an empirical process. For the improvement of the product quality, there is a need of more knowledge on this traditional process and the beer characteristics. The alcoholic fermentation is one of the most steps which most determines the quality of the beer. In this study, the characteristics of the traditional starter and the evolution of temperature, ethanol, sugars and organic acids were assessed at small-scale production during alcoholic fermentation of tchapalo. Brewers used traditional starter at the rate of 0.76-0.88 % when it was dried or at 2.38 % when it was not. When the wort was at 36.6-39.3 °C, the starter was added to initiate the fermentation. Temperature decreased to 34.6-36.5 °C at the end of the fermentation which was concluded after 7.6 h to 8.4 h. Sugars were consumed during the fermentation but it remained 12.9 to 16.57 g/L of reducing sugars and 8.02 to 9.12 °Brix of TSS in the final product. Ethanol content increased from 0.02-0.35 % (v/v) in the wort to 3.5-4.59 % in the beer. The oxalic, citric, tartaric, malic, lactic, fumaric and propionic acids were found in the wort and in tchapalo and increased or decreased during fermentation differently from one site to another. But, the acetic acid was not always detected in both the wort and the beer.

In Côte d’Ivoire, Cassava roots are mainly processed into attiéké, a kind of fermented cassava semolina, dried and steamed. This food, widely consumed, is produced by women according to a traditional technology requiring several hard operations. When the dough is not immediately processed into attiéké, it rots. Therefore, an improved process involving washing and storage of the fermented dough in a closed bucket was tested. This process lead to a stabilized dough which could be preserved for at least four weeks. The cyanide content in this dough represented 25% of the traditional one’s (39.50 ± 0.8 mg/kg). Both dough were safe of Enterobacteria. They mainly contained lactic acid bacteria (1 to 1.7×108 cfu/g) which grew during the stabilized dough storage. Attiéké from this dough was similar to the traditional attiéké. As stabilizing the fermented dough, the new process should encourage the growth of attiéké production efficiency, the producer incomes and cassava production increase.