Evaluation of Oat hull xylan as prebiotic for the novel strain of Lactobacillus brevis
(2020) KBTM01 20192Biotechnology (MSc)
Biotechnology (M.Sc.Eng.)
- Abstract
- In this study, the extraction and isolation of xylan from milled oat hull materials was investigated. Alkali extraction by 2 M sodium hydroxide at 40°C overnight was applied. The yield of extracted xylan was 5%. The extracted xylan was isolated from the extraction mixture by ethanol (99.9%) after neutralization and its purity was checked, resulting in a66% pure product. The semi-purified xylan was used for the enzymatic hydrolysis using the enzyme Pentopan mono BG aiming to break down (i.e. hydrolyse) the associated polysaccharide and produce xylooligosaccharides (XOS). The analysed hydrolysate showed that small amount of XOS were produced. Detection of 0.05% xylobiose (XOS2), 0.01% xylotriose (XOS3), 0.04% xylotetraose (XOS4), and 0.04%... (More)
- In this study, the extraction and isolation of xylan from milled oat hull materials was investigated. Alkali extraction by 2 M sodium hydroxide at 40°C overnight was applied. The yield of extracted xylan was 5%. The extracted xylan was isolated from the extraction mixture by ethanol (99.9%) after neutralization and its purity was checked, resulting in a66% pure product. The semi-purified xylan was used for the enzymatic hydrolysis using the enzyme Pentopan mono BG aiming to break down (i.e. hydrolyse) the associated polysaccharide and produce xylooligosaccharides (XOS). The analysed hydrolysate showed that small amount of XOS were produced. Detection of 0.05% xylobiose (XOS2), 0.01% xylotriose (XOS3), 0.04% xylotetraose (XOS4), and 0.04% arabinoxyloheptaose (AXOS6) were possible after enzymatic hydrolysis of 10 g/L of the purified arabinoxylan (AX).
Growth studies using the Lactobacillus brevis strain ks-13 on MRS medium were made using monosaccharides as well as the produced XOS as carbon source. The growth medium was supplemented with glucose (5,10, 15, 20 g/L), xylose (5, 20 g/L), or XOS (10 g/L of hydrolysate), separately. The results showed that L. brevis ks-13 can grow on different concentration of glucose. The maximum cell density (OD620nm) and maximum specific growth rate (µmax) of L.brevis ks-13 in the MRS medium supplemented with glucose 20 g/L were 15.56 and 0.65 h-1, respectively. Also, the L.brevis ks-13 could grow on xylose. The maximum cell density and specific growth rate of L.brevis ks-13 (OD620= 4.6 and µmax = 0.08 h-1 for 5 g/L xylose and OD=5 and µmax =0.12 h-1 for 20 g/L xylose was lower than that on glucose. The L.brevis ks-13 growth on MRS medium supplemented with 10 g/L of hydrolysate was also performed. However, the resulting chromatograms did unexpectedly not show any detectable peaks of XOS in the MRS medium, despite showing clear peaks when a corresponding concentration was dissolved in water. This indicates that the XOS must be precipitated in the MRS medium (something that has not been shown in previous studies using XOS from other resources). Despite not seeing the peaks, some growth was observed on the hydrolysate. . Short chain fatty acids (SCFA) production during the bacterial fermentation was investigated and the results showed the production of lactic acid with maximum concentration of 11.6,10.7, 0.8 g/L In the MRS medium supplemented with 20 g/L glucose, 20 g/L xylose, and 10 g/L hydrolysate, respectively. (Less) - Popular Abstract
- Over the recent decades due to the raise in public awareness regarding interrelationship of health and diet, prebiotics which are defined as ’non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and /or activity of one or a limited number of bacteria in the colon, and thus improves host health’ received a considerable attention. These valuable compounds not only have protective effects on the gastrointestinal system, but also other organs such as central nervous system, immune system and cardiovascular system are under their impact, and that’s why we hear ‘’ We are what we eat!’’. In this respect, the fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS) , inulin and (arabino)... (More)
- Over the recent decades due to the raise in public awareness regarding interrelationship of health and diet, prebiotics which are defined as ’non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and /or activity of one or a limited number of bacteria in the colon, and thus improves host health’ received a considerable attention. These valuable compounds not only have protective effects on the gastrointestinal system, but also other organs such as central nervous system, immune system and cardiovascular system are under their impact, and that’s why we hear ‘’ We are what we eat!’’. In this respect, the fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS) , inulin and (arabino) xylo-oligosaccharides (A)XOS are the most common and popular prebiotics.
Oat (Avena Sativa) is abundantly grown in Europe and many other regions and reported to be the 6th cereal major grain and oat industry generates large quantities of the by-product named Oat hull during de-hulling process. The oat hull is the outer envelope of the oat grain. Although oat hull is a main by-product of the oat industry, it has received little attention as a marketable commodity and additionally, its disposal is often an environmental problem.
This part of the whole grain have been classically burnt or used as animal feed for ruminants or bedding or industrially as an starting material for chemical solvent production, namely furfural and related furan compounds but the compositional analyses signifies that it has been evidently underutilized since it possess valuable potentials to be utilized as value-added products particularly in prebiotic xylooligosaccharides production.
The chemical composition of oat hull substantially contains cellulose, hemicellulose and lignin through which hemicellulose owing to containing arabinoxylan (AX) can be in the centre of further research in order to produce value-added products such as arabinoxylooligosaccharides (AXOS) with prebiotic potential for certain spectrum of probiotics that are defined as “living microorganisms with scientifically proven health beneficial effects when are adequately administered to the body”.
The intention of this research was to produce AXOS derived from oat hull through certain chemical pre-treatment aiming to isolate arabinoxylan followed by enzymatic treatment targeting AXOS production. AXOS were estimated to be utilized by the certain bacterial strain and so possess a notable potential as prebiotics. An in-vitro fermentation trial with an emerging probiotic strain(Lactobacillus brevis ks-13) was performed to evaluate the potential of achieved AXOS toward stimulate growth of this strain and monitor any short chain fatty acid (SCFA) production during the bacterial metabolism.
The results addressed the question of the potential to utilize oat hull derived AXOS by this probiotic bacterium to produce SCFA, regarded as the final product of oligosaccharides metabolism . (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9005849
- author
- Hasheminejad, Parisa LU
- supervisor
- organization
- course
- KBTM01 20192
- year
- 2020
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Oat hull xylan, Prebiotic L.brevis, Biotechnology
- language
- English
- additional info
- This version of the master's thesis is preliminarily uploaded to LUP and after final and complete revision by the examination, the final version will be uploaded.
- id
- 9005849
- date added to LUP
- 2020-03-02 10:51:08
- date last changed
- 2020-03-02 10:51:08
@misc{9005849,
abstract = {{In this study, the extraction and isolation of xylan from milled oat hull materials was investigated. Alkali extraction by 2 M sodium hydroxide at 40°C overnight was applied. The yield of extracted xylan was 5%. The extracted xylan was isolated from the extraction mixture by ethanol (99.9%) after neutralization and its purity was checked, resulting in a66% pure product. The semi-purified xylan was used for the enzymatic hydrolysis using the enzyme Pentopan mono BG aiming to break down (i.e. hydrolyse) the associated polysaccharide and produce xylooligosaccharides (XOS). The analysed hydrolysate showed that small amount of XOS were produced. Detection of 0.05% xylobiose (XOS2), 0.01% xylotriose (XOS3), 0.04% xylotetraose (XOS4), and 0.04% arabinoxyloheptaose (AXOS6) were possible after enzymatic hydrolysis of 10 g/L of the purified arabinoxylan (AX).
Growth studies using the Lactobacillus brevis strain ks-13 on MRS medium were made using monosaccharides as well as the produced XOS as carbon source. The growth medium was supplemented with glucose (5,10, 15, 20 g/L), xylose (5, 20 g/L), or XOS (10 g/L of hydrolysate), separately. The results showed that L. brevis ks-13 can grow on different concentration of glucose. The maximum cell density (OD620nm) and maximum specific growth rate (µmax) of L.brevis ks-13 in the MRS medium supplemented with glucose 20 g/L were 15.56 and 0.65 h-1, respectively. Also, the L.brevis ks-13 could grow on xylose. The maximum cell density and specific growth rate of L.brevis ks-13 (OD620= 4.6 and µmax = 0.08 h-1 for 5 g/L xylose and OD=5 and µmax =0.12 h-1 for 20 g/L xylose was lower than that on glucose. The L.brevis ks-13 growth on MRS medium supplemented with 10 g/L of hydrolysate was also performed. However, the resulting chromatograms did unexpectedly not show any detectable peaks of XOS in the MRS medium, despite showing clear peaks when a corresponding concentration was dissolved in water. This indicates that the XOS must be precipitated in the MRS medium (something that has not been shown in previous studies using XOS from other resources). Despite not seeing the peaks, some growth was observed on the hydrolysate. . Short chain fatty acids (SCFA) production during the bacterial fermentation was investigated and the results showed the production of lactic acid with maximum concentration of 11.6,10.7, 0.8 g/L In the MRS medium supplemented with 20 g/L glucose, 20 g/L xylose, and 10 g/L hydrolysate, respectively.}},
author = {{Hasheminejad, Parisa}},
language = {{eng}},
note = {{Student Paper}},
title = {{Evaluation of Oat hull xylan as prebiotic for the novel strain of Lactobacillus brevis}},
year = {{2020}},
}