Isolation and characterization of β-galactosidase positive Kluyveromyces spp. from dairy products

Abstract

K. marxianus and K. lactis happen to be the only lactose fermenting yeast species found regularly in milk products. These species are considered to be Generally Regarded As Safe organisms (GRAS) and have been approved as a food additive. Since, the information regarding the prevalence of Kluyveromyces spp. in dairy products is scanty especially under Indian conditions, hence an attempt has been made in the present study to isolate and characterize β-galactosidase positive Kluyveromyces spp. from dairy products. A total number of 110 randomly selected colonies were isolated from different dairy products. Out of these, 60 isolates were identified as Kluveromyces spp. after morphological and biochemical characterization. However, after molecular characterization, 18 isolates were confirmed as Kluyveromyces spp. Out of which 14 isolates were confirmed as K. marxianus and 4 as K. lactis . The present study has revealed that indigenous dairy products can be natural and preferred niche for isolation and growth of native and novel strains of dairy yeasts such as K. lactis and K. marxianus.