The convergence of biology, technology, and medicine has revolutionised healthcare, with microbial biotechnology at the forefront. While many microbes are often considered solely for their infectious properties, many are major producers of natural products, including antimicrobials. Now, not only sources of clinically relevant drugs, they are also being directly engineered for advanced applications such as targeted drug delivery, immune modulation, and precision therapeutics. Microorganisms are key sources of novel antimicrobials, immunomodulatory, and anticancer agents, which synthetic biology and genomics mining can exploit. Bioengineering and exploration of underused microbial taxa offer promising solutions to the problem of rising antimicrobial resistance. Microbes also play crucial roles in modern vaccine development, from live attenuated to recombinant antigen production. The human microbiome has emerged as an interesting player in health, driving innovations in diagnostics and therapies that include next-generation probiotics and microbiota transplants. Furthermore, synthetic biology further empowers the design of 'smart' microbes for in situ therapeutic functions like imaging, biosensing, and targeted treatment. While transformative, these innovations also raise critical ethical and regulatory concerns, including biosafety, ecological impact, data privacy, and equitable access. This chapter explores the multifaceted roles of microbes in medical biotechnology-spanning therapeutics, vaccines, microbiome-based interventions, and engineered systems-underscoring their importance in the evolution of sustainable, personalised healthcare.
Global food security has become one of the greatest challenges of the twenty-first century due to the rapidly growing world population's food demands and environmental threats such as climate change, soil erosion, and the depletion of freshwater resources. The extensive use of chemical fertilizers and pesticides throughout conventional agriculture has increased productivity significantly, but it has additionally resulted in major ecological and socioeconomic problems, such as soil acidity, groundwater resource pollution, and decreased biodiversity. In this regard, microbial biotechnology is a particularly noteworthy technique that improves agricultural production while promoting environmental sustainability, maintaining ecological balance, and making effective use of resources. This application makes use of microorganisms to enhance soil health and structure, promote plant growth, and minimize both abiotic and biotic stresses. Microbial applications include nitrogen fixation, as well as biofertilizers that reduce the dependency on synthetic materials and biopesticides. Microbial consortia and biostimulants that improve plant physiology by producing phytohormones produce more dependable and durable consequences in the field. Metagenomics and metabolomics are the two types of omic technologies used in these areas of study that provide a thorough description of the variety and roles of microorganisms. Furthermore, the intentional production of microbes targeted at specific organisms has been made practical via synthetic biology and gene editing techniques. In-depth case studies performed in several countries reveal that microbial technologies significantly reduced expenses and improved soil production, advancing the sustainable development goals. Nevertheless, there are several barriers to the widespread use of microbial biotechnology in agriculture. These include unpredictable conditions in the fields, strict regulations, especially related to genetically modified organisms' problems with product quality, and farmers' insufficient understanding. Microbial biotechnology aims to accomplish its full potential as an advancement in technology and as an essential aspect of resource-efficient and environmentally friendly agricultural systems via responsible innovation, adaptable regulations, and worldwide cooperation.
Omics technologies have revolutionized research across diverse fields, and their increasing use in microbiology has provided new opportunities for understanding microbial life. These methods enable detailed investigation of the molecular biology of individual organisms as well as the complex interactions within microbial communities. In this chapter, we describe key single-organism omics approaches, including genomics, transcriptomics, proteomics, and metabolomics, as well as meta-omics techniques such as metagenomics, metatranscriptomics, metaproteomics, and meta-metabolomics. We also discuss integrative multi-omics strategies for studying microbial ecosystems. For each omics method, we outline its main features, experimental and bioinformatic workflows, major applications, and commonly used computational tools, thereby providing a practical guide for researchers aiming to explore microbial structure, function and interactions at multiple molecular levels.
The human microbiota represents a complex and dynamic ecosystem composed of microorganisms from various taxonomic groups, including bacteria, viruses, fungi, archaea, and protozoa. These microorganisms inhabit different anatomical regions of the human body, such as the genitourinary system, the gastrointestinal tract, the oral cavity, the skin, and the respiratory tract, exhibiting distinct densities, compositions, and functional characteristics, and interact reciprocally with the host organism. The term microbiota not only defines the diversity and abundance of microorganisms but also encompasses their functional influence on host physiology. At this point, the concept of the microbiome becomes relevant. The microbiome refers to the collective genomic content of all microorganisms comprising the microbiota, that is, their genetic material and the potential biological functions encoded by their genes. Therefore, microbiome analysis enables not only the assessment of microbial diversity, but also of metabolic capacity, signal transduction, immune regulation, and other host-microbe interactions. The microbiota and microbiome play important roles in preserving human health and homeostatic balance. A healthy microbial composition promotes immune system development, aids digestion and nutrient absorption, reduces pathogenic microorganism colonization, and contributes to the integrity of the mucosal barrier. In contrast, dysbiosis, or disruption of microbial equilibrium, has been linked to a variety of pathophysiological illnesses, including inflammatory diseases, metabolic disorders, neurodegenerative diseases, and some neoplasms. Today, microbiome research is not only essential for understanding health and disease mechanisms but also forms the foundation for innovative future medical applications.
Bacteria exhibit extraordinary evolutionary and ecological diversity. They range from dominant, well-characterized phyla to rare lineages that are known only through environmental sequencing. This chapter reviews four key bacterial phyla, including Pseudomonadota, Bacillota, Actinomycetota, and Bacteroidota. These phyla are widely distributed, metabolically versatile, and play a central role in ecosystem functioning and human health. We discuss unique phyla within the PVC superphylum (Planctomycetota, Verrucomicrobiota, Chlamydiota) for their unusual cell biology, compartmentalization, and host associations. We also highlight hyperthermophilic phyla, such as Thermotogota, Aquificota, and Thermodesulfobacteriota, that thrive in geothermal ecosystems and drive sulfur and carbon cycling. We consider less-cultivated lineages, including Deinococcota, Acidobacteriota, Nitrospirota, Fusobacteriota, Fibrobacterota, Synergistota, Deferribacterota, and Chrysiogenota, in terms of their ecological niches, metabolic specializations, and roles in biogeochemical cycles, symbiosis, and disease. Collectively, these examples demonstrate the remarkable metabolic flexibility and ecological impact of bacteria, ranging from host-associated commensals and pathogens to free-living autotrophs in extreme environments. Despite advances in genomics and cultivation-independent methods, vast portions of bacterial diversity remain uncultured and poorly understood. Continued exploration of both dominant phyla and rare lineages promises to refine bacterial taxonomy, expand our understanding of microbial evolution, and reveal novel metabolic pathways with implications for ecology, medicine, and biotechnology.
