<abstract>
<p>Lignocellulosic crop waste is the world's most abundant renewable raw material. Its burning leads to the loss of an energy valuable resource and causes enormous environmental damage. An environmentally friendly and promising biotechnological process for such waste utilization is the production of mushrooms for food and medicine. However, the energy intensity of substrate preparation hinders the development of work in this direction. Another significant challenge in this field is to increase the biological efficiency of substrate processing. The purpose of our investigation was to reveal the contribution of microorganisms to solving this and other problems of mushroom cultivation based on a review of the latest scientific research on the topic. The literature from databases of Google Scholar, Scopus, and Web of Science was selected by various combinations of search queries concerning mushrooms, substrates, microbial communities, and their effects. The current state of the issue of mushrooms and microorganisms' interactions is presented. The review considers in detail the contribution of microorganisms to the substrate preparation, describes microbial communities in various phases of the mushroom cultivation process, and identifies the main groups of microorganisms associated with lignocellulose degradation, mushroom growth promotion, and protection against pathogens. The significant contribution of bacteria to mushroom cultivation is shown. The review demonstrates that the contribution of bacteria to lignin degradation in lignocellulosic substrates during mushroom cultivation is largely underestimated. In this process, various genera of the bacterial phyla <italic>Bacillota</italic>, <italic>Pseudomonadota</italic>, and <italic>Actinomycetota</italic> are involved. The correct combinations of microorganisms can provide controllability of the entire cultivation process and increase required indicators. However, expanding research in this direction is necessary to remove gaps in understanding the relationship between microorganisms and mushrooms.</p>
</abstract>
