Industrial waste accounts for a considerable amount of manmade waste streams, of which it is the most distinctly harmful to local environments if released untreated. Microbiological treatment of biodegradable waste materials ensures neutralization of harmful substances and allows for the reduction of environmental pollution. Additionally, conversion of these wastes into value-added products enables particular recycling efforts to become more economically viable. Single-cell protein is one such value-added product that can be derived from various waste materials via microbial fermentation. In this review various biodegradable industrial by-products as substrates for production of SCP are categorized and compared.