Lachnospiraceae are emerging industrial biocatalysts and biotherapeutics. This review summarizes recent advances in the physiology, cultivation, and genetics of Lachnospiraceae, highlighting their wide substrate utilization and metabolic products with industrial applications. The family includes anaerobic bacteria that can metabolize abundant, low-cost feedstocks such as lignocellulose and carbon dioxide into value-added chemicals. They are also dominant species in the human colon and animal rumen, where they ferment dietary fiber to promote gut and immune health. The review examines studies of these bacteria as Live Biotherapeutic Products (LBPs), focusing on in vivo disease models and clinical studies using them to treat infection, inflammation, metabolic syndrome, and cancer. Key research areas include elucidating intra-specific diversity and genetic modification of candidate strains to facilitate their use in industry and medicine. Lachnospiraceae are found in diverse ecosystems, including the gastrointestinal tracts of humans, mice, insects, and ruminants, as well as in anaerobic soil, aquatic sediments, Antarctic green snow, wastewater, and deep sea hydrothermal vents. Recent advances in genomics, cultivation, and genetic manipulation of these bacteria have enabled a better understanding of their roles in gut and environmental ecosystems. The review discusses the phylogeny and genomes of Lachnospiraceae, their substrate utilization, and metabolic products, including alcohols, gases, and acids with importance in industry and human health. Lachnospiraceae are also a potential source of antimicrobial and immunomodulatory compounds. The review also covers cultivation and engineering of Lachnospiraceae, including methods for genetic modification and the development of genetic tools for their study. The potential applications of Lachnospiraceae in the bioeconomy include converting low-cost, sustainable lignocellulosic feedstocks into value-added biochemicals. Therapeutic applications include preclinical and clinical studies showing that supplementation with live Lachnospiraceae improves gut health and prevents pathogen colonization. Lachnospiraceae have also been shown to alleviate inflammatory and allergic diseases by modulating the immune system through production of antigens presented by innate immune cells and immunomodulatory metabolites. The review highlights the challenges and opportunities in harnessing Lachnospiraceae as industrial biocatalysts and LBPs, including the need to isolate and characterize additional strains, uncover the genetic basis of their physiological traits, and apply these findings to engineer optimized strains. The review concludes that further research is needed to fully realize the potential of Lachnospiraceae in biotechnology and medicine.Lachnospiraceae are emerging industrial biocatalysts and biotherapeutics. This review summarizes recent advances in the physiology, cultivation, and genetics of Lachnospiraceae, highlighting their wide substrate utilization and metabolic products with industrial applications. The family includes anaerobic bacteria that can metabolize abundant, low-cost feedstocks such as lignocellulose and carbon dioxide into value-added chemicals. They are also dominant species in the human colon and animal rumen, where they ferment dietary fiber to promote gut and immune health. The review examines studies of these bacteria as Live Biotherapeutic Products (LBPs), focusing on in vivo disease models and clinical studies using them to treat infection, inflammation, metabolic syndrome, and cancer. Key research areas include elucidating intra-specific diversity and genetic modification of candidate strains to facilitate their use in industry and medicine. Lachnospiraceae are found in diverse ecosystems, including the gastrointestinal tracts of humans, mice, insects, and ruminants, as well as in anaerobic soil, aquatic sediments, Antarctic green snow, wastewater, and deep sea hydrothermal vents. Recent advances in genomics, cultivation, and genetic manipulation of these bacteria have enabled a better understanding of their roles in gut and environmental ecosystems. The review discusses the phylogeny and genomes of Lachnospiraceae, their substrate utilization, and metabolic products, including alcohols, gases, and acids with importance in industry and human health. Lachnospiraceae are also a potential source of antimicrobial and immunomodulatory compounds. The review also covers cultivation and engineering of Lachnospiraceae, including methods for genetic modification and the development of genetic tools for their study. The potential applications of Lachnospiraceae in the bioeconomy include converting low-cost, sustainable lignocellulosic feedstocks into value-added biochemicals. Therapeutic applications include preclinical and clinical studies showing that supplementation with live Lachnospiraceae improves gut health and prevents pathogen colonization. Lachnospiraceae have also been shown to alleviate inflammatory and allergic diseases by modulating the immune system through production of antigens presented by innate immune cells and immunomodulatory metabolites. The review highlights the challenges and opportunities in harnessing Lachnospiraceae as industrial biocatalysts and LBPs, including the need to isolate and characterize additional strains, uncover the genetic basis of their physiological traits, and apply these findings to engineer optimized strains. The review concludes that further research is needed to fully realize the potential of Lachnospiraceae in biotechnology and medicine.