Genetic engineering involves the transfer of genes from one organism to an unrelated species. Genetic engineering is being used in the production of pharmaceuticals, gene therapy, and the development of transgenic plants and animals. Transgenic plants may be obtained by using the plasmid of the bacterium Agrobacterium tumefaciens. Transgenic animals are produced by microinjection of foreign DNA into fertilized eggs or by using retrovirus for introducing foreign DNA into early embryonic stages.

Animal breeding enhances livestock genetics by selecting animals with superior traits, improving growth rates and production of eggs, meat, milk, or wool. This has advanced global livestock and plant production. Transgenic technology further improves livestock by enhancing reproduction, feed utilization, growth rates, carcass composition, milk production, hair or fiber quality, and disease resistance. Gene transfer rapidly modifies livestock genomes.

Tissue culture allows for rapid, large-scale propagation of plants like palm trees, orchids, bananas, and carrots. This technique enables the production of high-quality food in small areas. Genetic engineering has also created seedless fruits such as watermelon, papaya, orange, and grape, helping to reduce crop cycles

Biotechnology applications in health include the production of human drugs like insulin for diabetes, growth hormone for dwarfism, and tissue plasminogen activator for heart attacks, using transgenic bacteria and pigs. Antibiotics are produced by microorganisms such as Streptomyces for streptomycin and Penicillium for penicillin, which can be chemically modified for different diseases. Vaccines are produced on a large scale for diseases like pertussis, typhoid, cholera, and tuberculosis. Biosensors detect biochemical changes and measure substances like pollutants and vitamins, and are notable for food quality monitoring. Forensic science applies scientific methods to crime investigation, including DNA analysis and fingerprinting.

Biomining utilizes microorganisms to extract valuable metals from ores and waste materials in an environmentally friendly and cost-effective manner. This process, part of biohydrometallurgy, relies on microbes like Acidithiobacillus ferrooxidans to oxidize sulfide minerals, replacing traditional methods. Beyond metal extraction, biomining aids in environmental sustainability through solid waste treatment, composting, wastewater treatment, bioremediation, and biofuel production. It plays a crucial role in managing waste, reducing pollution, and recovering resources. Bioremediation is an eco-friendly technique that employs microorganisms, plants, or their enzymes to detoxify polluted environments by degrading, removing, or neutralizing contaminants in soil, water, and air. This process utilizes biodegradation and biotransformation to convert toxic pollutants into less harmful substances. Biofuel, a renewable energy source, is derived from organic materials such as plant crops and animal waste. Typically produced through the fermentation of plant materials, biofuels like ethanol serve as alternatives to fossil fuels by breaking down cellulose and hemicellulose into fermentable sugars with the help of enzymes. Biogas is a combustible gas created from the anaerobic breakdown of organic matter, such as manure and crop waste, by bacteria and archaea. It mainly consists of methane and carbon dioxide and requires specific anaerobic microbial communities for its production.

Biological warfare (BW), or germ warfare, involves using biological toxins or infectious agents like bacteria, viruses, and fungi to kill or incapacitate humans, animals, or plants in wartime. Biological weapons encompass any microorganism or toxin designed to cause harm, and bioterrorism can vary from hoaxes to actual deployment of these agents