Reports of Actinomycetes to Degrade Microplastic

Microplastics, originating from a variety of polymers, range in size from 1 μm to 5 mm. Because of their tiny size, reduced density, structure, and endurance in the surroundings, microplastics spread throughout the world via ocean currents. Microplastics are microscopic sized particles used in cosmetics, homes and industrial cleaning products, and have accumulated in aquatic as well as terrestrial ecosystem. Microplastics can be consumed by numerous marine animals by mistaking them as phytoplankton and these will accumulate in the food chain causing serious health problems. Thus, the degradation of these microplastics is inevitable and it can be done in two ways—abiotic and biotic. The abiotic degradation of microplastics can be done by thermal, mechanical, and chemical means, while in biotic degradation, microbial enzymes work to breakdown polymers. Several reports suggest the role of fungi and bacteria in degrading the microplastics but actinomycetes, a Gram-positive bacteria present ubiquitously help in the biodegradation process of microplastics. A little amount of actinomycetes can form a layer of biofilm around the polymer and aids in its degradation viz. Rhodococcus ruber. Rhodococcus rhodochrous degrades the microplastics after getting treatment with abiotic factors. Actinomyces in combination with bacteria changes the physical, chemical structure of the microplastics polluting the environment which leads to its degradation. Microplastic deterioration in the environment is triggered with a pre-treatment of nitric acid before applying on the actinomycetes Microbacterium paraoxydans. Numerous actinomycetes break down the micron sized polymers by secreting such enzymes which has high degrading capability. Some novel marine-derived actinomycetes like Streptomyces gougerotii, Micromonospora matsumotoense, and Nocardiopsis prasina degrade different microplastics and use them as a source of carbon to produce biodegradable plastics.