Study on isolation of potentially probiotic Lactobacillus species from fermented rice

N Jeygowri,S Ranadheera,S Jeyatilake,N Parahitiyawa,T Madhujith

doi:10.4038/tar.v26i3.8106

N Jeygowri, S Ranadheera + Show 3 more

Open Access

https://doi.org/10.4038/tar.v26i3.8106

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Abstract

Traditional fermented food products such as fermented rice are known to possess probiotic potential. Probiotics are live microorganisms that provide a myriad of health benefits. Despite the associated health benefits, fermented rice has not received due attention in the countries where rice is the staple diet. Many strains of probiotic bacteria have been isolated from different sources, however, not much work has been carried out on isolation of probiotic strains from fermented rice. In this backdrop, the present study was carried out to isolate and identify potentially probiotic microorganisms from fermented rice. Cooked and uncooked white and red rice were separately fermented and subsequently used to isolate potentially probiotic strains. The Man Rogosa Sharpe (MRS), MRS sorbitol (0.2%) and MRS L-cysteine (0.5%) culture media were used for the isolation of potentially probiotic bacteria. The samples of fermented rice were serially diluted, plated and incubated at 37°C for 2-3 days under anaerobic conditions. The resulting colonies were purified and tested for catalase production and Gram-staining. Distinct cluster like cocci, diplo cocci and rods were observed with gram-positive and catalase-negative reactions. Most of the isolated cluster like cocci morphologically resembled Aercococcus or Peptococcus species. The rods were selected for motility and endospore test and sugar fermentation was studied using API 50CH kits. The biochemical characteristics (gram positivity and catalase-negativity) non-motile and non-endospore forming and colony and cell morphology of seven rod shaped bacteria resembled the genus Lactobacillus and were identified to species level by API 50CH kits. The subsequent physiological and molecular methods for species identification and probiotic characterization of these seven Lactobacillus spp will further confirm the application of them as potential probiotic starter cultures in the food industry. Tropical Agricultural Research Vol. 26 (3): 428 – 440 (2015)

Highlights

Probiotics are live microorganisms used as food supplements, which provide health benefits when consumed, through improving the intestinal microbial balance of the host (Fuller, 1989).They are live microorganisms which when administered in adequate amounts confer health benefits on the host (FAO-WHO, 2001)
The number of studied colonies showed that the majority of the isolated microorganisms from fermented rice was grape like clusters of coccus and isolated rods with similar number of diplococcus
Karna and Barraquio (2007) found in their study of fermented milk product, That the predominant genus was Lactobacillu sp., which comprised fifteen of twenty eight isolates while others included Pediococcus (5), Bifidobacterium (6) and Actinomycesis israelii (2) .274 strains of Lactobacilli sp were identified among 563 total isolates from Thai traditional fermented food (Srikanjana et al, 2008) Another study (Silvia and Medana, 2011) reported that fermented Romanian vegetables were rich source of Lactic Acid Bacteria (LAB) including 139 isolates with rod- (95) coccoid (32), cocobacillai (11) and diplococcal (1) shapes

Summary

Introduction

Probiotics are live microorganisms used as food supplements, which provide health benefits when consumed, through improving the intestinal microbial balance of the host (Fuller, 1989).They are live microorganisms which when administered in adequate amounts confer health benefits on the host (FAO-WHO, 2001). Microorganisms commonly used as Isolation of Potentially Probiotic Lactobacillus species probiotics include Bifidobacteria, Lactobacilli and certain yeasts. Research has shown that addition of probiotics to food provides many a health benefit. They are able to increase the frequency of bowel movements (Bekkali et al, 2007) and stimulate cell-mediated immunity (Wold, 2001). Fermentation is one of the primary methods of adding value to food including improving palatability, safety, shelf life and nutritional value. This process could be applied in the production of functional foods such as probiotic food (Salovaara and Simson, 2004)

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