Paraprobiotics and postbiotics from the probiotic Streptococcus lutetiensis isolated from Indian fermented food demonstrates immunomodulatory potential

Abstract

Paraprobiotics and postbiotics are emerging as innovative solutions for improving human health. They offer distinct advantages that can bypass the side effects associated with live probiotics in immunocompromised individuals. This study investigates the functional potential of Streptococcus lutetiensis isolated from pakhala bhata, a traditionally fermented Indian food, focusing on its probiotic characteristics, paraprobiotic and postbiotic preparations, metabolite profiling, and immunomodulatory effects. The strain exhibited key probiotic attributes such as gastrointestinal tolerance, auto-aggregation, cell-surface hydrophobicity, non-hemolytic nature, as well as antimicrobial and antioxidant properties. In vitro studies with THP-1 macrophages revealed that paraprobiotics and postbiotics from Strep. lutetiensis modulated cytokine patterns similar to live probiotics. Of the 27 cytokines analyzed, 15 cytokines were secreted by both paraprobiotics and probiotics. Paraprobiotics induced higher IL-8 and IL-5 levels, while postbiotics increased that of G-CSF, IL-10, and MIP-1b. Metabolite profiling of paraprobiotics and postbiotics by GCMS and HPLC identified 26 and 33 compounds, respectively, including organic acids, alcohols, fatty acids, peptides, esters, aldehydes, and ketones, which likely contribute to their antimicrobial and antioxidant activity. Overall, the investigated strain Strep. lutetiensis is a good probiotic, with paraprobiotics exhibiting immunomodulatory properties warranting further validation through animal trials. The key novelty of this research lies in the multipurpose potential of Strep. lutetiensis obtained from relatively unexplored East Indian fermented food pakhala bhata (fermented rice). This study systematically confirms its probiotic, paraprobiotic, and postbiotic potential, specifically through characterizing the composition of postbiotics as well as paraprobiotics and comparing their immune-stimulating effects at the secretion level in human macrophages.