Environmental isolates, genetically manipulated organisms, plants, animals and their products and economical methods are being expertly explored to biosynthesize poly-3-hydroxybutyrate plastics of comparable properties to petroplastics. This study assessed a hypothesized feasibility of utilizing a proliferative pleustophytic greenery, water hyacinth (Eichhornia crassipes (Mart.) Solms-Laubach) in Lake Victoria, Uganda as a potential carbon source for poly-3-hydroxybutyrate biosynthesis. The poly-3-hydroxybutyrate biosynthesizing bacteria (Bacillus megaterium) was isolated from municipal sewage sludge and harnessed for batch fermentation of acid-catalysed water hyacinth biomass. Poly-3-hydroxybutyrate formed in the cytoplasm of the bacterial cells was extracted by chloroform extraction method, and thereof confirmed and quantified by UV spectroscopy. Batch fermentation was carried out in 100ml of the culture media in a 250ml fermenter for different times (48, 96, 144 and 192 hours) to determine the best incubation time for maximum yield. An all-out net yield of 61.3% was realized after 96 hours of fermentation. Utilization of this ecological plague for poly-3-hydroxybutyrate biosynthesis is a promising strategy for regulating the weed population along the length of Nile River and the Victorian basin.