Microbiome: A Source of Novel Bioactive Compounds and Antimicrobial Peptides 19 Garima Suneja, Sonam Nain, and Rakesh Sharma Abstract The human body is an abode for trillions of microbes that have co-evolved with humans and are beneficial in several ways. Human oral cavity, gut, and skin have been shown to harbor abundant and diverse microbial communities. Other body parts, some of which were previously considered to be sterile, have also been shown to possess a number of resident bacteria. The microbial inhabitants on or in human body are largely commensals. Many of these organisms produce small bioactive molecules or peptides that interact with other bacteria to inhibit/modify their growth and colonization or with the host to modulate the host immune response. This chapter briefly discusses the microbial diversity of human body and presents a detailed account of antimicrobial peptides and bioactive molecules identified from these microorganisms and their potential applications. Keywords Microbiome · Bioactive compounds · Bacteriocin · Antimicrobial · Immunomodulatory · Anticancer · Human metagenome · Biosynthetic cluster G. Suneja · S. Nain · R. Sharma (*) Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, Delhi, India Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre (CSIR-HRDC), Ghaziabad, Uttar Pradesh, India e-mail: rsharma@igib.res.in # Springer Nature Singapore Pte Ltd. 2019 T. Satyanarayana et al. (eds.), Microbial Diversity in Ecosystem Sustainability and Biotechnological Applications, https://doi.org/10.1007/978-981-13-8315-1_19 615