QPCR-Guided Screening of Levansucrase: Levan Characterization and Genomic Insights

Abstract

Eighty-seven bacteria isolates were screened for the presence of the levansucrase encoding gene and those possessing the gene were used in gene expression studies and the production of levan. Based on both screening methods, isolate P19-1 was determined as the producer bacterium with the highest amounts of levan. Whole genome sequencing was done to characterize the isolate and determine its genomic potential. Both its 16 S rRNA and genome were closest to Chromohalobacter salexigens. The levansucrase gene and genes suggesting a versatile carbohydrate and nitrogen metabolism were annotated. A secondary metabolism suggestive of a possible new role in promoting plant growth in hypersaline environments was revealed. The chemical structure analysis of the produced polymer was confirmed by comparison with commercial pure Erwinia herbicola levan. Also, C. salexigens levan showed high biocompatibility. Overall, this is a practical molecular approach that will help researchers to effectively screen microbes with levan production potential.