ABSTRACT
Every year up to 5 billion tons of biowaste (husks, stalks, peels, bagasse, cake) can be generated by agro-industry; hence, the management of these residues is a well-known concern that carries environmental damage by greenhouse emissions, land, and water contamination. Although the accumulation of agroindustrial waste represents a global threat, it is also an opportunity to develop a sustainable, low-cost, and renewable alternative to produce high-value 202bioproducts by microbial fermentation, such as carotenoids, oil, and enzymes. However, the complex composition of agro-industrial waste hinders its utilization as a substrate in submerged fermentation. For that reason, ecoinnovative treatments (i.e., ultrasound, subcritical extraction, and enzymatic hydrolysis) can be used to ease the conversion of macromolecules to simple compounds, such as sugars, amino acids, and minerals, which can be easily assimilated by microorganisms. In this respect, yeasts are cell factories that have been exploited in the food industry due to their capacity to assimilate various carbon and nitrogen sources with high cellular yields in short growth cycles. Also, yeast demands neither large cultivation areas nor climacteric conditions; hence, these advantages make yeast a potential alternative source for producing natural value-added products. Therefore, agro-industrial waste valorization as an alternative feedstock in yeast biotechnology reduces the negative environmental effect of waste disposal and raw material expenses, which generally has the most sensitive effect on the bioproduct manufacturing cost. This chapter couples applying innovative green methods and yeast cultivation for agro-industrial waste valorization into high-value bioproducts to contribute to a circular and sustainable bioeconomy.
