Mapping Four Decades of Microbial Waste Valorization Research in Africa through a Systematic Review and Bibliometric Analysis

The annual Africa waste production has been predicted to triple by 2050. Due to lack of proper waste disposal plans and services in many African countries, wastes are indiscriminately dumped leading to environmental and human health issues. Microorganisms with their complex biochemical functionaries play a significant role in waste valorization. Research in the application of microorganisms in waste conversion has been ongoing globally. However, there i no information on the extent of research on this subject with regards to Africa using bibliometric and systematic review approaches. This study was aimed at understanding the extent of research in microbially-driven waste valorization in Africa to identify research gaps and future perspectives. Bibliographic and systematic literature review (SLR) methodology guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were used for this study. Bibliographic data (752) was extracted from Scopus database. Thereafter, 264 data were excluded and the remaining 488 data were analysed using Biblioshiny, Vosviewer and Excel analytical tools. Nigeria with 369 published articles ranked above other countries from 1984-2024. However, using the number of citations and single country publication (SCP) South Africa dominated with 3233 and 75% SCP. Themes like wastewater treatment, composting, recycling, and microorganisms evolved to biodegradation, biomass, microbial community, anaerobic digestion etc. The findings suggest that emerging themes are still revolving around biomass and anaerobic digestion, as more research is still on wastewater treatment and management, recycling and fermentations in waste valorization. This knowledge contributes to future research designing and gap identification in the area of waste valorization in Africa.