Anaerobic digestion (AD) is an efficient and sustainable way of using organic carbon from residual biomass and organic waste for the production of renewable energy, while simultaneously recycling nutrients and cleaning up waste streams. The process relies on complex microbial communities comprised of diverse functional guilds; these communities have manifold metabolic pathways and interactions. In contrast to the conventional view of an anaerobic digester as a black box, advanced microbiological methods have paved the way for understanding and even controlling complex microbial networks. Nowadays, microbial resource management is crucial for technological progress in AD, and offers new perspectives concerning sustainable waste management, renewable energy production, resource efficiency, and advanced bio-refineries; these perspectives lead to novel applications of AD processes that go beyond biogas as the main product. [...].