A newly isolated strain of Trichoderma atroviride AD-130 was used to produce cellulases under submerged fermentation (SmF) using low-cost lignocellulosic substrates, water hyacinth, and municipal solid wastes. Although, the synthesis of β-glucosidase enzyme remains deficient in most of the Trichoderma spp. but the same was found considerably higher in the newly isolated fungus. Untreated and dried lignocellulosic biomasses of water hyacinth (Eichhornia crassipes) and municipal solid wastes were used as abundant and cost-effective substrates. Trichoderma atroviride AD-130 showed the highest cellulase activity on the fourth day of incubation at pH 7.0, temperature 30°C, 2% substrate concentration, and agitation speed of 180 rpm under submerged fermentation. The cellulase production decreased sharply when any of the optimized factors, whether pH, temperature, substrate concentration, or agitation speed was either increased or decreased beyond the optimized ones. Also, the poised proportion of FPase and β-glucosidase secreted by the cited fungus could have helped in completing the hydrolytic procedure efficiently.