The present invention relates to a novel thermophilic ethanol producing yeast strain, a microorganism, Kluyveromyces sp. IIPE453 MTCC 5314, classified as yeast, which exhibits growth and sugar fermentation at higher temperature range between 37° C. to 55° C. The novel yeast strain is capable of utilizing wide range of mono and di-saccharide sugars belongs to hexose and pentose carbohydrate family individually or in a mixture that obtained from hydrolysis of lignocellulosic biomass, such as sugarcane bagasse or starch based biomass such as cassava, potato, corn etc. for its growth and produce ethanol by fermentation process at temperature range 40° C. to 55° C. It also relates to a novel process for the preparation of ethanol by Kluyveromyces species IIPE453. Thus application of thermophilic yeast strain Kluyveromyces sp. IIPE453 MTCC 5314 has wide scope for industrial production of bioethanol from low cost renewable biomass as alternate feedstock to molasses.