Dynamics of microbial populations and metabolites of fermenting saps throughout tapping process of ron and oil palm trees in Côte d'Ivoire.

Palm wine fermentation is a complex microbial process that evolves with tapping times. The dynamics in microbiota and metabolites throughout palm wine tapping days is still not established, which are critical for the distinctive characteristics of palm wine taste and quality, and thus the mastery of the daily quality fluctuation during tapping. We analyzed the changes in microbial community structure by amplicon sequencing of bacterial 16S rRNA gene and fungal internal transcribed spacer (ITS) region, and metabolite profile changes using mass spectrometry in palm wine collected over 25-30 days tapping of ron (Borassus aethiopum) and oil palms (Elaeis guineensis) from Côte d'Ivoire. The stage-wise collected palm wine samples showed distinct changes in microbial diversity and pH, supporting microbial community dynamics during palm wine tapping. Results highlighted the dominance of Saccharomyces cerevisiae in early stages and the emergence of non-Saccharomyces yeasts, particularly Hanseniaspora spp. in the later stages of oil palm wine tapping, vice versa in the case of ron palm wine tapping, with a unique presence of Saccharomycodes in the later stages (15-30 days). Fructophilic lactic acid bacteria (FLAB), mainly Fructobacillus and Leuconostoc, encountered in both types of palm wine tapping showed a decline at later stages of oil palm wine tapping. In this type of palm wine, acetic acid bacteria with genera Acetobacter and Glucanoacetobacter, by surpassing Lactobacillus in the last stage become dominant, whereas Lactobacillus remained dominant in ron palm wine throughout tapping days. The decline in the relative abundance of gevotroline and essential amino acids during the later stages of palm wine tapping (15-25 days) supports the difference in the health benefits of the palm wine obtained from different days of tapping, indicating that early stages of tapping is more nutritional and healthy than the later stages. The microbial dynamics may be a potential indicator of metabolite changes during palm sap fermentation, thus contributing to establish particular features of palm wines in different stages of tapping. This understanding of microbial ecology and chemical composition changes during palm wine tapping can be used as biomarkers to assess palm wine's quality and help to design an optimum starter culture.

Characterization of a Potential Isozyme Laccase from Trametes polyzona MPS1-3 and its Contribution to Palm Oil Mill Effluent Treatment.

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 Côte 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.

Phenotypic characterization of indigenous Saccharomyces cerevisiae strains associated with sorghum beer and palm wines.

In order to phenotypically characterized Saccharomyces cerevisiae strains isolated from sorghum beer and palm wines for a possible selection of a starter culture, 30 strains were tested for killer activity, temperature resistance, ethanol tolerance, carbohydrate fermentation, enzyme profile and sorghum wort fermentation. Of the tested strains, three showed a killer profile, while four showed a neutral profile and 23 were found to be sensitive to K2 toxin. Temperatures of 40 °C and 44 °C allowed to distinguish strains into four thermal groups with only three strains may grow at 44 °C. Almost tested strains were tolerant to 5% ethanol with viability rates up to 73%. But at 10% and 15% ethanol, respectively 18 and 7 strains were tolerant. Carbohydrate fermentation revealed 13 fermentation profiles, including one typical and 12 atypical profiles. The typical profile strains (16.13% of the strains) fermented glucose, galactose, fructose, sucrose, maltose, trehalose and raffinose. Most of the strains secreted lipases (mainly esterase and esterase-lipase), proteases (mainly valine and cysteine arylamidase, chrymotrypsin) and phosphatases (mainly acid phosphatase and naphthol phosphohydrolase). On contrary, only five strains isolated from sorghum beer exhibited glucosidase activity, mainly α-glucosidase. The analyse of fermented sorghum wort revealed that fermentative performance is strain dependent. Furthermore, the Hierarchical Cluster Analysis showed that the strains were separated in three distinct clusters with the strains from sorghum beer clustered separately.

Microbial Diversity and Metabolite Profiles of Palm Wine Produced From Three Different Palm Tree Species in Côte d'Ivoire.

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.

Genetic diversity and population structure of Saccharomyces cerevisiae strains isolated from traditional alcoholic beverages of Côte d'Ivoire.

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.

Molecular identification of yeast, lactic and acetic acid bacteria species during spoilage of tchapalo, a traditional sorghum beer from Côte d'Ivoire.

Yeasts, lactic and acetic acid bacteria are responsible of microbial spoilage of alcoholic beverages. However species involved in deterioration of sorghum beer produced in Côte d'Ivoire has not been investigated. This study was carried out to identify species of yeast, LAB and AAB during spoilage of tchapalo in order to define the best strategy for beer preservative. Thus, a total of 210 yeasts, LAB and AAB were isolated from samples of tchapalo stored at ambient temperature and at 4 °C for 3 days. Based on PCR-RFLP of the ITS region and the sequencing of D1/D2 domain, yeast isolates were assigned to seven species (Saccharomyces cerevisiae, Candida tropicalis, Rhodotorula mucilaginosa, Trichosporon asahii, Kluyveromyces marxianus, Meyerozyma guilliermondii and Trichosporon coremiiforme). During the storage at ambient temperature and at 4 °C, S. cerevisiae was the predominant species (> 76%). Excepted R. mucilaginosa, occurrence of non-Saccharomyces species was sporadic. LAB species detected in fresh samples using molecular methods were Pediococcus acidilactici, Lactobacillus paracasei, Lb. curvatus, Lb. fermentum and Weisssella paramesenteroides. P. acidilactici was the dominant species (47.8%) followed by Lb. paracasei (17.5%). W. paramesenteroides and Lb. fermentum were not detected during the spoilage at ambient temperature while at 4 °C W. paramesenteroides and Lb. paracasei have not been detected. For AAB, the species found were Acetobacter pasteurianus sub paradoxus and Acetobacter cerevisiae. These species were common to all samples during spoilage and A. pasteurianus sub paradoxus was the most frequently detected.

Identification of yeasts isolated from raffia wine (Raphia hookeri) produced in Côte d'Ivoire and genotyping of Saccharomyces cerevisiae strains by PCR inter-delta.

Raffia wine is a traditional alcoholic beverage produced in several African countries where it plays a significant role in traditional customs and population diet. Alcoholic fermentation of this beverage is ensured by a complex natural yeast flora which plays a decisive role in the quality of the final product. This present study aims to evaluate the distribution and the diversity of the yeast strains isolated in raffia wine from four sampling areas (Abengourou, Alépé, Grand-Lahou and Adzopé) in Côte d'Ivoire. Based on the D1/D2 domain of the LSU rDNA sequence analysis, nine species belonging to six genera were distinguished. With a percentage of 69.5 % out of 171 yeast isolates, Saccharomyces cerevisiae was the predominant species in the raffia wine, followed by Kodamaea ohmeri (20.4 %). The other species isolated were Candida haemulonii (4.1 %), Candida phangngensis (1.8 %), Pichia kudriavzevii (1.2 %), Hanseniaspora jakobsenii (1.2 %), Candida silvae (0.6 %), Hanseniaspora guilliermondii (0.6 %) and Meyerozyma caribbica (0.6 %). The molecular characterization of S. cerevisiae isolates at the strain level using the PCR-interdelta method revealed the presence of 21 profiles (named I to XXI) within 115 isolates. Only four profiles (I, III, V and XI) were shared by the four areas under study. Phenotypic characterization of K. ohmeri strains showed two subgroups for sugar fermentation and no diversity for the nitrogen compound assimilations and the growth at different temperatures.