Effect of bacteria type and sucrose concentration on levan yield and its molecular weight

Abstract

BackgroundLevan has been traditionally produced from microorganism. However, there is a continuous effort in looking for new strains that improve levan production yield and uses alternative sugar sources for growth. Despite having a wide range of data about levan yield, there are not papers which allow controlling molecular weight, and that plays an essential role for further applications.ResultsThe effect of the sucrose concentration on levan yield (and its molecular weight) from Bacillus atrophaeus and Acinetobacter nectaris (Gram positive and Gram negative respectively) was studied in this work. It was found that A. nectaris growth (from 3 to 1.5 g L−1 in 40 h) and its levan production (from 3 to 1.5 g L−1) decreases by increasing sucrose concentration (best results at a concentration of 120 g L−1) whereas B. atrophaeus growth (3.5 g L−1 in 30 h) and its levan production (also 3.5 g L−1) were not affected by modifying that parameter. Levan molecular weight from A. nectaris decreases by increasing sucrose concentration (from 8000 to 2000 kDa) whereas levan molecular weight from B. Atrophaeus remains always around 50 kDa. By performing a kinetic study, it was shown that A. nectaris growth follows a substrate-inhibition model, whereas Monod equation provided a good fit for B. atrophaeus growth. Finally, wastes from orange juice industry were used as a medium culture to cultivate those microorganism, obtaining good results with B. atrophaeus (growth 3 g L−1 in 30 h).ConclusionsLevan production kinetics was determined and compared between different bacteria types.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-017-0703-z) contains supplementary material, which is available to authorized users.

Bioactive Levan-Type Exopolysaccharide Produced by Pantoea agglomerans ZMR7: Characterization and Optimization for Enhanced Production

“…This enzyme works efficiently when sucrose is used as a sole carbon source and displays low activity with other types of sugars such as raffinose, mannose, fructose, glucose, and others [10]. Levan is considered as a water-soluble biopolymer that is also soluble in oil because it contains the β- (2,6) linkage. On the other hand, this biopolymer is insoluble in a wide range of organic solvents such as ethanol, methanol, acetone, isopropanol, toluene, etc.…”

Studies on solvent precipitation of levan synthesized using Bacillus subtilis MTCC 441

“…The gene responsible for levan production is found to be SacB which gets activated by the presence of sucrose (Porras-Dominguez et al., 2017). Microorganisms such as Zymomonas mobilis (Jang et al., 2001; Silbir et al., 2014), Bacillus subtilis natto (Shih et al., 2010a,b) , Bacillus licheniformis (Kekez et al., 2015); (Xavier and Ramana, 2017) , Clostridium acetobutylicum (Gao et al., 2017) , Brennia goodwinii (Liu et al., 2017; Xu et al., 2017) , Acinetobacter nectaris (Gonzalez-Garcinuno et al., 2017). , Lactobacillus reuteri (Ni et al., 2018), Halomonas sp., (Poli et al., 2009; Sarilmiser and Oner, 2014), Gluconoacetobacter xylinus, Microbacterium laevaniformans, Rahnella aquatilis (Yoo et al., 2004), Xanthomonas (Fuchs, 1956) , Saccharomyces (Franken et al., 2013) , Pseudomonas (Kasapis et al., 1994; Laue et al., 2006) , Streptococcus (Newbrun and Baker, 1968; Simms et al., 1990) etc.…”

Sustainable Production of Pulque and Maguey in Mexico: Current Situation and Perspectives

“…This bacterium can grow on glucose and oxidizes D-fructose and sucrose. Remarkably, produces levan from sucrose by a periplasmic levansucrase (Álvarez-Pérez et al, 2013;González-Garcinuño et al, 2017). High sugar content in aguamiel supposes a suitable environment for this bacterium.…”