Optimized chromogenic dyes-based identification and quantitative evaluation of bacterial l-asparaginase with low/no glutaminase activity bioprospected from pristine niches in Indian trans-Himalaya

Abstract

Here, we report on the isolation of bacterial isolates from Himalayan niches, which produced extracellular l-asparaginase with low/no glutaminase activity. From the 235 isolates, 85 asparaginase positive bacterial isolates were identified by qualitative screening using optimized chromogenic dyes assay. Optimized concentration of different dyes revealed maximum color visualization in phenol red (0.003%). The diversity analysis of asparaginase positive isolates revealed that Proteobacteria (83%) are the most dominant, followed by Actinobacteria (12%), Firmicutes (3%), and Bacteriodetes (2%). Eleven isolates, which represented seven Pseudomonas species, one species each of the genus Arthrobacter, Janthinobacterium, Lelliottia, and Rahnella, were selected for further studies based on highest zone ratio and novel aspects for l-asparaginase production. Of these, five isolates, namely, Pseudomonas sp. PCH133, Pseudomonas sp. PCH146, Pseudomonas sp. PCH182, Rahnella sp. PCH162, and Arthrobacter sp. PCH138, produced l-asparaginase without glutaminase activity after 55 h of growth with the former isolate showing the highest l-asparaginase activity (1.67 U/ml). Interestingly, this is the first report of l-asparaginase production by members of the genera Janthinobacterium, Rahnella, and Lelliottia.

Microbial pigments: Learning from Himalayan perspective to industrial applications

“…Thus, efforts are required to explore its hidden treasures. Our lab focuses on bioprospecting high-altitude Himalayan microbiomes for basic and applied research (Kumar et al., 2018a , 2019 , 2020 , 2021 , 2022 ; Thakur et al., 2018 ; Ambika et al., 2022 ). The isolation and identification of various pigment-producing bacteria from the high-altitude Himalayan region were accomplished during the course.…”

Biochemical characterization of extremozyme L-asparaginase from Pseudomonas sp. PCH199 for therapeutics

“…In consistence to exploration, our group has also screened various niches in the western Himalayan region for efficient L-ASNase with improved properties compared to existing L-ASNases (Kumar et al 2019 ; Kumar et al 2022a , 2022b ). Notably, the Himalayan niches such as glacier surfaces, glacier streams, and mineral-rich soil harbour microbial life with remarkable adaptive properties.…”

“…Notably, the Himalayan niches such as glacier surfaces, glacier streams, and mineral-rich soil harbour microbial life with remarkable adaptive properties. Extreme conditions of the Himalayas like temperature fluctuations, survival in low oxygen, tolerance to salt and pH fluctuations, low pressure, and high UV radiations bestowed the bioresources with uniqueness (Kumar et al 2019 ). Hence, realizing the importance of Himalayan niches, the existing scope for finding pH and temperature stable functional enzymes are a boon to pharmaceutical and food industries.…”

Multiple Adaptive Strategies of Himalayan Iodobacter sp. PCH194 to High-Altitude Stresses

“…The Himalayas host a range of environmental niches such as permafrost, glacial streams, lakes, sediments, meadows, and deserts that contain distinct microbial communities (Stres et al, 2013 ; Kumar et al, 2018 , 2019 , 2022 ; Thakur et al, 2018 ; Dhakar and Pandey, 2020 ). High-altitude Himalayan environments are characterized by multiple stress factors such as high UV irradiation, oxidative stress, frequent freeze-thaw cycles, desiccation, oxygen limitation, nutritional fluctuation, and perennially cold temperatures (Singh and Singh, 2004 ; Stres et al, 2013 ).…”