Abstract:
Lake Victoria, the second-largest freshwater lake in the world, provides an important source of food and income, particularly fish
for both domestic consumption and for export market. In recent years, Lake Victoria has suffered massive pollution from both
industrial and wastewater discharge. Microplastic biomes, pharmaceutical residues, drugs of abuse, heavy metals,
agrochemicals, and personal care products are ubiquitous in the aquatic ecosystem of Winam Gulf. These pollutants are
known to alter microbial assemblages in aquatic ecosystems with far-reaching ramification including a calamitous consequence
to human health. Indeed, some of these pollutants have been associated with human cancers and antimicrobial resistance.
There is a paucity of data on the microbial profiles of this important but heavily polluted aquatic ecosystem. The current study
sought to investigate the metagenomic profiles of microbial assemblages in the Winam Gulf ecosystem. Water and sediment
samples were collected from several locations within the study sites. Total genomic DNA pooled from all sampling sites was
extracted and analyzed by whole-genome shotgun sequencing. Analyses revealed three major kingdoms: bacteria, archaea and
eukaryotes belonging to 3 phyla, 13 classes, 14 families, 9 orders, 14 genera, and 10 species. Proteobacteria, Betaproteobacteria,
Comamonadaceae, Burkholdariales, and Arcobacter were the dominated phyla, class, family, order, genera, and species,
respectively. The Kyoto Encyclopedia of Genes and Genomes indicated the highest number of genes involved in metabolism.
The presence of carbohydrate metabolism genes and enzymes was used to infer organic pollutions from sewage and
agricultural runoffs. Similarly, the presence of xylene and nutrotoluene degradation genes and enzyme was used to infer
industrial pollution into the lake. Drug metabolism genes lend credence to the possibility of pharmaceutical pollutants in
water. Taken together, there is a clear indication of massive pollution. In addition, carbohydrate-active enzymes were the most
abundant and included genes in glycoside hydrolases. Shotgun metagenomic analyses conveyed an understanding of the
microbial communities of the massively polluted aquatic ecosystem of Winam Gulf, Lake Vicoria, Kenya. The current study
documents the presence of multiclass pollutants in Lake Victoria and reveals information that might be useful for a potential
bioremediation strategy using the native microbial communities
