Algae were discovered to be edible when man began to search the natural world for food. Protein levels in these algae were higher than in animals and plants, and they required far less water to generate than other species. Subsequently, food security is deemed vital for the existing population and global climate change, and algae are an alternative meal for individuals suffering from nutritional shortages. Since algae is abundant in antioxidant components, its bioactive chemicals can treat a variety of conditions, including high blood pressure, heart disease, diabetes, and cancer. These algae effectively utilize carbon dioxide emissions, increasing oxygen production and preserving the balance of the planet. Additionally, these algae store carbon dioxide and use it to create a variety of useful and profitable goods. When man looked for algae not only as food but also as an alternative energy source, they discovered that biofuel from algae is eco-system-friendly and reduces global warming to some extent. Algae also has several uses in agriculture, including improving soil fertility, restoring soil, controlling pests, forming microbial crusts, treating agricultural effluent, and recycling fresh water. Algae not only as food but also as fertilizer is an important contribution to plant growth by improving its physiological antagonistic reactions. Because this bio-fertilizer is rich in micro- and macronutrients, fiber ash is rich in carbohydrates and plant growth-promoting factors. It is environmentally friendly and inexpensive, making it a suitable biofertilizer for alternative agriculture. Technical training in kelp production and quality management for producers can lead to more sustainable kelp development. Thus, it is an inevitable fact that the quality and utility of these multipurpose algae should be further enhanced through research-validated techniques. The micro- and macronutrients in this biofertilizer make fiber ash rich in carbohydrates and plant growth-promoting elements. It is an appropriate biofertilizer for alternative agriculture because it is affordable and environmentally benign. A more sustainable kelp development can be achieved by providing farmers with technical training in kelp production and quality control. Therefore, it is given that through procedures supported by research, the quality and usefulness of these multipurpose algae should be further improved.