Microbial extracellular enzymes occupied a prominent place in industrial sector due to their multifunctional ability. Extensive application of these, gap between production and demand is widening. In order to fulfil this gap, researchers focusing on various strain improvement methods such as recombinant and non-recombinant mutagenesis. In the present research work we made an attempt to screen high yielding industrial important extracellular alginase producing Bacillus tropicus CUIMW1718 strain by treating with inexpensive mutagens such as UV, EMS and EtBr. In this indigenous strain was subjected to Ultraviolet (UV) irradiation, Ethidium bromide (EtBr), Ethyl Methane Sulfonate (EMS) mutagenesis, followed by cross mutation of Ultraviolet (UV) irradiated strain with Ethyl Methane Sulfonate (EMS) and Ethidium bromide (EtBr). High yielding mutant strains were selected based on zone of clearance.