Aalborg Universitet

Butyric acid fermentation from pretreated and hydrolyzed wheat straw byC.tyrobutyricum

Baroi, George Nabin; Westermann, Peter; Gavala, Hariklia N.

Publication date:2013

Document VersionAccepted author manuscript, peer reviewed version

Link to publication from Aalborg University

Citation for published version (APA):Baroi, G. N., Westermann, P., & Gavala, H. N. (2013). Butyric acid fermentation from pretreated and hydrolyzedwheat straw by C.tyrobutyricum. Poster presented at International Conference on Industrial biotechnology –meeting the challenges, Lund, Sweden.

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Butyric acid fermentation from pretreated and hydrolyzed wheat straw by C.tyrobutyricum

Baroi, G.N , Westermann P., Gavala H.N.* Aalborg University Copenhagen (AAU-Cph), Department of Biotechnology, Chemistry and Environmental Engineering, A C Meyers Vænge 15, DK 2450 Copenhagen SV Denmark. *hng@bio.aau.dk

Background Butyric acid and its esters are used as food supplements, artificial flavours, solvent and even its potential beneficial effects in intestinal and extra intestinal diseases and sickle cell disease have been reported. It can be used for production of bio-plastics (e.g. cellulose acetate

butyrate). Another potential use of butyric acid is to produce butanol via catalytic hydrogenation. The demand of the butyric acid is approximately 50,000 ton/year. The main bottlenecks of commercialization of biological production of acids ( in overall) are: (1) utilization of cheap feed stocks

(2) Proper strain selection &/or improvement (3) Process development. Within SUPRABIO, we aim to develop a process for cost-efficient biological production of butyric acid from wheat straw.

Conclusion The developed strain ( C. tyrobutyricum) could grow in up to 80% PHWS with higher yield (> 4,4 g/g) and selectivity (>90%). The developed process increased the productivity over 200%, most probably by decreasing inhibitory effects .

Acknowledgement

The authors wish to thank the Commission of the European Communities for the financial support of this work under SUPRABIO project (FP7-cooperation project no 241640).

Food

Animal feed

Bio-fuels

Bio-chemicals

Composite materials

Crafts

Others

Pilot scale fermentation

Pretreatment (Biogasol®)

Enzymatic hydrolysis (Biogasol®)

Strain selection and development

Process development

In-situ product separation

(Jurag separation A/S technology)

Process scheme of butyric acid production from wheat straw Exploitation of wheat plant

0.32 0,34 0,35 0,36

0,47 0,39 0,37

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0,10

0,20

0,30

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0,50

40% 45% 50% 55% 60% 70% 80%

% (v/v) of Pretreated and hydrolysed wheat straw (PHWS)

Butyric acid yield (g/g sugars) in different concentration of PHWS

Acetic acid yield (g/g sugars) in different concentration of PHWS

0,00

0,05

0,10

0,15

40% 45% 50% 55% 60% 70% 80%

% of Pre-treated and hydrolysed wheat straw (PHWS)

012345678

0 50 100 150 200

Co

nce

ntr

atio

n (

g/l

)

Time (h)

Glucose Xylose Arabinose Acetate Butyrate

PHWS pulse Feeding

0

0,2

0,4

0,6

0,8

1

7 6 5

Yie

ld (

g/g

),

se

lect

ivit

y (g

/g a

cid

s)

pH

Yacetate Ybutyrate Selectivity

Yields and selectivity under different pH Simultaneous uptake of glucose and xylose in PHWS

0,0

0,5

1,0

1,5

2,0

0 50 100 150

OD

66

0

Hours

A B C

0

20

40

60

80

Glucose Butyric acid Acetic acid

Rat

e (

g/d

ay)

Remain in the fermentor

Extracted by REED

Metabolized

Growth inhibition from K+ ion concentrations (A= 6,315gK + /l; B=12,629gK + /l; C=18,944gK +/l)

Continuous in-situ separation of butyric acid

Key Outcomes

Stra

in d

eve

lop

me

nt

P

roce

ss d

eve

lop

me

nt