Enrichment Strategies for Polyhydroxyalkanotaes (Pha) Production from Fermented Crude Glycerol Using Microbial Mixed Cultures

Anna Burniol-Figols*, C. Varrone, A. E. Daugaard, I. V. Skiadas, H. N. Gavala

*Corresponding author for this work

Research output: Contribution to conferenceConference abstract for conferenceResearchpeer-review

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Abstract

Polyhydroxyalkanoates (PHA) are biopolymers produced as internal carbon storage in bacteria. They are a potential alternative to petroleum derived plastics, although their competitiveness is still limited by their productions costs. These could be lowered by the use of waste substrates - such as crude glycerol, a major by-product of the biodiesel industry- and microbial mixed cultures - which do not require sterilisation 1.
An important limitation for the PHA production from glycerol is the side accumulation of glycogen, a polymer with no market value. This can be circumvented by submitting first the substrate to anaerobic fermentation to produce volatile fatty acids (VFA), which are preferred substrates for PHA production2. However, the fermentation also leads to 1,3-propanediol (1,3-PDO), a compound not previously described for PHA production.
Initial experiments aimed at the transformation of both VFA and 1,3-PDO to PHA. Using the classical feast-famine enrichment strategy, PHA production from 1,3-PDO was not observed. Conversely, the transformation was achieved by using a new strategy that limited the nitrogen during the feast phase. Nevertheless, the PHA yield obtained form 1,3-PDO was very low compared to the one obtained from VFA (0.24 vs 0.74 Cmol PHA/Cmol S).
Given that 1,3-PDO is also a high value product, a third enrichment strategy was applied where only VFA were converted into PHA (up to 70% of the cells dry matter with a yield of 0.9 Cmol PHA/Cmol S) and 1,3-PDO was recovered from the process (97% recovery) in a biorefinery scheme. This strategy, based on the development of substrate preferences in mixed cultures, has the potential of being applied in other downstream processes of biological conversions, where fermentation side-products could be transformed into a high value product (PHA).
Original languageEnglish
Publication date2017
Number of pages1
Publication statusPublished - 2017
Event13th International Conference on Renewable Resources and Biorefineries - Wroclaw, Poland
Duration: 7 Jun 20179 Jun 2017
Conference number: 13
http://www.rrbconference.com/rrb13-2017

Conference

Conference13th International Conference on Renewable Resources and Biorefineries
Number13
CountryPoland
CityWroclaw
Period07/06/201709/06/2017
Internet address

Cite this

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title = "Enrichment Strategies for Polyhydroxyalkanotaes (Pha) Production from Fermented Crude Glycerol Using Microbial Mixed Cultures",
abstract = "Polyhydroxyalkanoates (PHA) are biopolymers produced as internal carbon storage in bacteria. They are a potential alternative to petroleum derived plastics, although their competitiveness is still limited by their productions costs. These could be lowered by the use of waste substrates - such as crude glycerol, a major by-product of the biodiesel industry- and microbial mixed cultures - which do not require sterilisation 1.An important limitation for the PHA production from glycerol is the side accumulation of glycogen, a polymer with no market value. This can be circumvented by submitting first the substrate to anaerobic fermentation to produce volatile fatty acids (VFA), which are preferred substrates for PHA production2. However, the fermentation also leads to 1,3-propanediol (1,3-PDO), a compound not previously described for PHA production.Initial experiments aimed at the transformation of both VFA and 1,3-PDO to PHA. Using the classical feast-famine enrichment strategy, PHA production from 1,3-PDO was not observed. Conversely, the transformation was achieved by using a new strategy that limited the nitrogen during the feast phase. Nevertheless, the PHA yield obtained form 1,3-PDO was very low compared to the one obtained from VFA (0.24 vs 0.74 Cmol PHA/Cmol S).Given that 1,3-PDO is also a high value product, a third enrichment strategy was applied where only VFA were converted into PHA (up to 70{\%} of the cells dry matter with a yield of 0.9 Cmol PHA/Cmol S) and 1,3-PDO was recovered from the process (97{\%} recovery) in a biorefinery scheme. This strategy, based on the development of substrate preferences in mixed cultures, has the potential of being applied in other downstream processes of biological conversions, where fermentation side-products could be transformed into a high value product (PHA).",
author = "Anna Burniol-Figols and C. Varrone and Daugaard, {A. E.} and Skiadas, {I. V.} and Gavala, {H. N.}",
year = "2017",
language = "English",
note = "13th International Conference on Renewable Resources and Biorefineries, RRB ; Conference date: 07-06-2017 Through 09-06-2017",
url = "http://www.rrbconference.com/rrb13-2017",

}

Burniol-Figols, A, Varrone, C, Daugaard, AE, Skiadas, IV & Gavala, HN 2017, 'Enrichment Strategies for Polyhydroxyalkanotaes (Pha) Production from Fermented Crude Glycerol Using Microbial Mixed Cultures', 13th International Conference on Renewable Resources and Biorefineries, Wroclaw, Poland, 07/06/2017 - 09/06/2017.

Enrichment Strategies for Polyhydroxyalkanotaes (Pha) Production from Fermented Crude Glycerol Using Microbial Mixed Cultures. / Burniol-Figols, Anna; Varrone, C.; Daugaard, A. E.; Skiadas, I. V.; Gavala, H. N.

2017. Abstract from 13th International Conference on Renewable Resources and Biorefineries, Wroclaw, Poland.

Research output: Contribution to conferenceConference abstract for conferenceResearchpeer-review

TY - ABST

T1 - Enrichment Strategies for Polyhydroxyalkanotaes (Pha) Production from Fermented Crude Glycerol Using Microbial Mixed Cultures

AU - Burniol-Figols, Anna

AU - Varrone, C.

AU - Daugaard, A. E.

AU - Skiadas, I. V.

AU - Gavala, H. N.

PY - 2017

Y1 - 2017

N2 - Polyhydroxyalkanoates (PHA) are biopolymers produced as internal carbon storage in bacteria. They are a potential alternative to petroleum derived plastics, although their competitiveness is still limited by their productions costs. These could be lowered by the use of waste substrates - such as crude glycerol, a major by-product of the biodiesel industry- and microbial mixed cultures - which do not require sterilisation 1.An important limitation for the PHA production from glycerol is the side accumulation of glycogen, a polymer with no market value. This can be circumvented by submitting first the substrate to anaerobic fermentation to produce volatile fatty acids (VFA), which are preferred substrates for PHA production2. However, the fermentation also leads to 1,3-propanediol (1,3-PDO), a compound not previously described for PHA production.Initial experiments aimed at the transformation of both VFA and 1,3-PDO to PHA. Using the classical feast-famine enrichment strategy, PHA production from 1,3-PDO was not observed. Conversely, the transformation was achieved by using a new strategy that limited the nitrogen during the feast phase. Nevertheless, the PHA yield obtained form 1,3-PDO was very low compared to the one obtained from VFA (0.24 vs 0.74 Cmol PHA/Cmol S).Given that 1,3-PDO is also a high value product, a third enrichment strategy was applied where only VFA were converted into PHA (up to 70% of the cells dry matter with a yield of 0.9 Cmol PHA/Cmol S) and 1,3-PDO was recovered from the process (97% recovery) in a biorefinery scheme. This strategy, based on the development of substrate preferences in mixed cultures, has the potential of being applied in other downstream processes of biological conversions, where fermentation side-products could be transformed into a high value product (PHA).

AB - Polyhydroxyalkanoates (PHA) are biopolymers produced as internal carbon storage in bacteria. They are a potential alternative to petroleum derived plastics, although their competitiveness is still limited by their productions costs. These could be lowered by the use of waste substrates - such as crude glycerol, a major by-product of the biodiesel industry- and microbial mixed cultures - which do not require sterilisation 1.An important limitation for the PHA production from glycerol is the side accumulation of glycogen, a polymer with no market value. This can be circumvented by submitting first the substrate to anaerobic fermentation to produce volatile fatty acids (VFA), which are preferred substrates for PHA production2. However, the fermentation also leads to 1,3-propanediol (1,3-PDO), a compound not previously described for PHA production.Initial experiments aimed at the transformation of both VFA and 1,3-PDO to PHA. Using the classical feast-famine enrichment strategy, PHA production from 1,3-PDO was not observed. Conversely, the transformation was achieved by using a new strategy that limited the nitrogen during the feast phase. Nevertheless, the PHA yield obtained form 1,3-PDO was very low compared to the one obtained from VFA (0.24 vs 0.74 Cmol PHA/Cmol S).Given that 1,3-PDO is also a high value product, a third enrichment strategy was applied where only VFA were converted into PHA (up to 70% of the cells dry matter with a yield of 0.9 Cmol PHA/Cmol S) and 1,3-PDO was recovered from the process (97% recovery) in a biorefinery scheme. This strategy, based on the development of substrate preferences in mixed cultures, has the potential of being applied in other downstream processes of biological conversions, where fermentation side-products could be transformed into a high value product (PHA).

M3 - Conference abstract for conference

ER -

Burniol-Figols A, Varrone C, Daugaard AE, Skiadas IV, Gavala HN. Enrichment Strategies for Polyhydroxyalkanotaes (Pha) Production from Fermented Crude Glycerol Using Microbial Mixed Cultures. 2017. Abstract from 13th International Conference on Renewable Resources and Biorefineries, Wroclaw, Poland.