Cyanobacteria or blue-green algae contain chlorophyll, but are similar in morphology to bacteria. Although unicellular, cyanobacteria form colonies held together by a pelatinous capsule. Cyanobacteria grow abundantly in jute fields where they act as nitrogen fixers, providing fertilizer to the plants. Another use of cyanobacteria is in retting jute and other bast fibers. A prepared medium accelerates the growth of cyanobacteria prior to inoculation of the retting tank. The medium, which can also be used to inoculate jute fields, consists of soil, cow dung, urea, and muriate of postash. Jute rets within 15 days with the inoculum, and fiber color improves significantly.