Sustainable Single-Cell Protein Production from Agro-Industrial Wastes: Biotechnology, Fermentation, and Biorefinery Strategies

Abstract

The growing global demand for sustainable protein sources and the increasing burden of agro-industrial waste have intensified interest in Single Cell Protein (SCP) as an alternative to traditional proteins. SCP, produced from microorganisms such as bacteria, yeasts, fungi, and algae, offers a promising solution for both protein shortages and waste valorization. This review critically examines the types and biochemical composition of agro-industrial wastes and their suitability for microbial growth. Key challenges, including substrate variability, contamination risks, and inconsistent supply chains, are highlighted as significant barriers to process standardization and product quality. The review also explores various microorganisms used in SCP production, their metabolic capabilities, and associated safety concerns. Additionally, it evaluates essential pre-treatment and processing methods needed to convert complex wastes into bioavailable substrates, emphasizing the importance of cost-effective and sustainable techniques. Nutritional and safety aspects of SCP, particularly nucleic acid content, allergenicity, and residual toxins, are discussed in the context of food and feed safety regulations. The study identifies future research priorities, such as genetic engineering, process optimization, and improved downstream processing to enhance SCP yield and market acceptance. The potential of SCP production to support circular bioeconomies, contribute to food security, reduce waste, and mitigate climate change is also emphasized. This review offers valuable insights into the opportunities, challenges, and socio-economic implications of sustainable SCP production from agro-industrial wastes for researchers, industry stakeholders, and policymakers.