Kalın Bağırsak Mikroflorasını Düzenlemek ve Bütirat Üretimini Artırmak için Sindirilemeyen Yüksek Oranda Dallanmış Yapıya Sahip Alfa Glukanların Enzimatik Olarak Sentezlenmesi

Increased

consumption of resistant starch or its derivatives has been shown to promote

butyrogenic bacteria and butyrate levels in the colon, which is associated with

beneficial health outcomes, including suppressing

the development of carcinogenesis, obesity, type-2-diabetes and inflammation.

Accordingly, increased amount of resistant starch consumption is suggested.

However, undesired pasting and gelling properties of resistant starch as well

as its instability in food formulations restrict its application as a prebiotic

(butyrate promoting) ingredient in many food products. Thus, there is a need

for developing functional ingredients that is chemically similar to, but do not

possess the undesirable technological properties of, starch. <o:p></o:p>

Since the

last decade, different types of α-glucans, that possess starch-like structures have

been biocatalytically synthesized, which are mainly used to lower the glycemic index

of starch. Moreover, the majority of such glucans have been shown to resistant

to mammalian digestive enzymes. Thus, they have great potential to show

butyrogenic effect as high as starch. However, there is no study conducted to

test the butyrogenic potentials of enzymatically synthesized α-glucans. This

project aims to fill this gap in the literature and discover optimum α-glucan

structure that reveals high butyrogenic activity and thus could be utilized

as a healthy ingredient for the productions of functional and medicinal foods. Further,

it is aimed to determine and isolate the beneficial microbial strain(s) from

the human feces that are promoted by the enzymatically synthesized α-glucan.<o:p></o:p>

The working

hypothesis of the

project is that since the enzymatically synthesized α-glucans possess

starch-like chemical structures (glucose units linked via α-1,4 and α-1,6

linkages), they could promote butyrogenic bacteria, thereby increasing the

butyrate level in the colon. The

primary objective is to enzymatically

synthesize α-glucans that have distinct structural features and determine their butyrogenic capacity. The goal is to enzymatically

synthesize insoluble α-glucans having different branching ratios using a simultaneous one-pot reaction approach

and investigate their effects on colonic microbiota composition in vitro

using 16S rRNA sequencing technology and on microbial metabolites by measuring

the amounts of short chain fatty acids using gas chromatography. Moreover, applicability

of the α-glucan (that is found to reveal

the highest butyrogenic effect) in food formulations will be evaluated using bread and yogurt as model foods. Additionally,

the microbial strain(s) that are favored by the α-glucan will be identified and isolated using both enrichment and plating techniques under

anaerobic conditions. <o:p></o:p>

Our expected

results are that we will explore the optimum α-glucan structure that promotes

butyrate producing bacteria and butyrate in the colon. Additionally, we will

identify and isolate microbial strain(s) that are favored by α-glucan of our

interest. These nutrients can be utilized as functional ingredients in the food

industry for the productions of healthy foods and can be directly extended to

studies in animals/humans. The positive impact of this work is to

advance our understanding of the connections between dietary fiber chemical

structures and colonic microbiome and to discover new functional food

ingredients that would have the potential to be patented and

commercialized for the productions of functional and medicinal foods.<o:p></o:p>

An international collaboration as proposed here will be important to carry out this

multidisciplinary project, as it requires multiple partners who complement each other in the areas of carbohydrate

chemistry and microbiology. Moreover,

such collaboration will increase our interaction with the South Korean Scientists

(Dr. Byung-Hoo Lee's group), thereby allowing us to conduct internationally collaborative

projects in future, which will scientifically increase the visibility of jointing

institutions and countries world-wide.