Removal of Small-Molecular Byproducts from Crude Fructo-Oligosaccharide Preparations by Fermentation Using the Endospore-Forming Probiotic Bacillus coagulans

Abstract

Short-chain prebiotic fructo-oligosaccharides (FOS) produced by enzymatic conversion from sucrose often contains high concentration of monosaccharides as byproducts. In addition to conventional physical/chemical purification processes, microbial treatment is an alternative method to remove these byproducts. We used Bacillus coagulans to reduce the abundance of byproducts during the enzymatic production of FOS. It is a promising probiotic because this thermophilic and spore-forming bacterium remains viable and stable during food processing and storage. B. coagulans also produces lactic acid during the carbohydrate metabolism and is used industrially to produce lactic acid for medical and food/feed applications. We aimed to establish an evaluation system to screen different strains of B. coagulans for their performance and selected B. coagulans Thorne for the treatment of crude FOS due to its high growth rate, high sporulation rate, and low nutrient requirements. B. coagulans preferentially utilized monosaccharides over other sugar components of the FOS mixture. Glucose and fructose were completely consumed during the fermentation but 85% (w/w) of the total FOS remained. At the end of the fermentation, the total viable cell count of B. coagulans Thorne was 9.9 × 108 cfu·mL−1 and the maximum endospore count was 2.42 × 104 cfu·mL−1.

Purification of Crude Fructo-Oligosaccharide Preparations Using Probiotic Bacteria for the Selective Fermentation of Monosaccharide Byproducts

“…The crude FOS solution produced by the commercial enzyme preparation Pectinex Ultra SP-L contained 28.3 g·l −1 fructose, 148.3 g·l −1 glucose, 71.3 g·l −1 sucrose, 163.6 g·l −1 1-kestose, 172.2 g·l −1 nystose, and 16.6 g·l −1 1F-fructofuranosylnystose. This was comparable to the results of previous experiments under similar conditions ( Aslan and Tanrıseven, 2007 ; Fan et al, 2020b ). Given the high concentration of carbohydrates, this stock solution was diluted in the medium for the cultivation of probiotic bacteria with a glucose concentration of 20 g·l −1 , thus avoiding any inhibitory effects.…”

“…The concentration of each component in the FOS solution was determined by ultra-high-performance liquid chromatography (UHPLC) as previously described ( Fan et al, 2020b ). Lactate concentrations were measured using a Biosen C line GP device (EKF-diagnostic, Barleben, Germany).…”

“…In recent decade, a novel application of probiotic microorganisms was reported in the literature. Probiotics such as Saccharomyces cerevisiae and Bacillus coagulans are used for the microbial purification of enzymatically produced crude FOS preparations, which also contain non-prebiotic monosaccharide byproducts and disaccharides ( Nobre et al, 2016 ; Srivastava and Mishra, 2019 ; Fan et al, 2020a , b ). The monosaccharides and disaccharides are removed to enhance the purity of FOS, and the monosaccharaides are converted into valuable byproducts such as organic acids and biomass, increasing the economic returns of the process.…”

“…The crude product usually contains FOS, unreacted sucrose, and monosaccharide byproducts such as fructose and glucose. Our previous investigation revealed that B. coagulans can selectively consume small sugar molecules to increase the purity of FOS ( Fan et al, 2020b ). However, this preliminary study is still far from enough to be applied in practical process for FOS purification.…”

Process Design for the Production of Prebiotic Oligosaccharides in an Enzyme Membrane Bioreactor: Interaction between Enzymatic Reaction and Membrane Filtration

“…The FTase used to produce FOS was secreted by a recombinant strain of Pichia pastoris, which was cultivated as previously described [18,19]. The synthesis of FOS was initiated by mixing the enzyme solution with 600 g L -1 sucrose (buffered with 100 mM potassium phosphate, pH 6.0) at a 1:9 (v:v) ratio.…”