Green Biotechnology: Principles, Applications and Sustainable Innovations explores the application of biotechnology to sustainable agriculture, renewable energy, environmental protection and climate-change mitigation. The book covers biofertilizers, biopesticides, plant growth-promoting rhizobacteria and biotechnological methods for improving crop productivity. It discusses bioethanol, biodiesel, biomass enhancement, waste-to-energy systems and engineered plants for alternative fuel production. Environmental applications include microbial degradation of plastics, bioremediation, phytoremediation, pollution monitoring and circular-economy-based resource utilization. The book also examines carbon sequestration, methane management, nutrient cycling, phytase-producing microorganisms and genetic engineering for improved photosynthesis and nutrient-use efficiency. Marker-free transgenic technologies, CRISPR-based crop improvement, biosafety, food security and sustainable-development policies are also addressed. It is intended for students and researchers in biotechnology, agriculture, microbiology and environmental science.