The environmental impact of the increasing anthropogenic CO2 emissions and the depletion of essential resources, once subjects of concern only for a minority of specialists, are now in the focus of many institutions and are de facto top priorities in many agendas. The ensuing environmental regulations, improved safety requirements, and growing critical public view on the chemical industry are the main reasons for an intense search for alternative synthetic routes to commodity chemicals and specialty chemicals. The skillful utilization of waste biomass, an inexhaustible resource, is revealed to be an important tool for a balanced CO(2 )management and the way to promising feedstock for many chemical and biochemical syntheses. The scope of the present contribution is to outline the main differences between chemical and biotechnological synthesis routes starting from waste biomass, focusing on C4-chemicals as an exemplary case study.