ReviewValorization of organic residues for the production of added value chemicals: A contribution to the bio-based economy

Establishing of a bio-based and green society depends on the availability of inexpensive organic carbon compounds, which can be converted by microbes into various valuable products. Around 3.7 × 109 t of agricultural residues and 1.3 × 109 t of food residues occur annually worldwide. This enormous amount of organic material is basically considered as waste and incinerated, anaerobically digested or composted for the production of heat, power or fertilizers. However, organic residues can be used as nutrient sources in biotechnological processes. For example, organic residues can be hydrolyzed to glucose, amino acids and phosphate by chemical and/or biological methods, which are utilizable as nutrients by many microbes. This approach paves the way toward the establishment of a bio-based economy and an effective organic residues valorization for the formation of bio-based chemicals and materials. In this review, valorization of organic residues in biotechnological processes is presented. The focus is on the production of three industrially important added value chemicals, namely succinic acid, lactic acid and fatty acid-based plasticizer, which have been used for the synthesis of environmentally benign materials and food supplements. Furthermore, utilization strategies of residues coming from fruit and vegetable processing are introduced.