TY - JOUR
T1 - Functional redundancy ensures performance robustness in 3-stage PHA-producing mixed cultures under variable feed operation
AU - Carvalho, Gilda
AU - Pedras, Inês
AU - Karst, Soren M.
AU - Oliveira, Catarina S. S.
AU - Duque, Anouk F.
AU - Nielsen, Per H.
AU - Reis, Maria A. M.
N1 - This work was supported by Fundacao para a Ciencia e a Tecnologia, Portugal (through projects PTDC/AGR-ALI/122741/2010, UID/Multi/04378/2013 and grants SFRH/BPD/88817/2012 and SFRH/BPD/88705/2012), by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007728), by the Danish Research Council for Strategic Research (EcoDesign-MBR), and by the EU through the project Ecoefficient Biodegradable Composite Advanced Packaging (EcoBioCAP), EU Integrated Project (FP7), contract No. 0265669; 2011-2015.
PY - 2018/1/25
Y1 - 2018/1/25
N2 - Polyhydroxyalkanoates (PHA) are biopolymers that can be produced by mixed microbial cultures using wastes or industrial by-products, which represent an economical and environmental advantage over pure culture processes. The use of alternate feedstocks enables using seasonal by-products, providing that the process is resilient to transient conditions. The mixed microbial communities of a 3-stage PHA producing system fed initially with molasses and then cheese whey were investigated through amplicon sequencing of the 16S rRNA gene. The transition in feedstock resulted in an adaptation of the acidogenic community, where Actinobacteria dominated with sugarcane molasses (up to 93% of the operational taxonomic units) and Firmicutes, with cheese whey (up to 97%). The resulting fermentation products profile also changed, with a higher fraction of HV precursors obtained with molasses than cheese whey (7.1 ± 0.5 and 1.7 ± 0.7 gCOD/L, respectively). As for the PHA storing culture, the genera Azoarcus, Thauera and Paracoccus were enriched with fermented molasses (average 89% of Bacteria). Later, fermented cheese whey fostered a higher diversity, including some less characterised PHA-storers such as the genera Paenibacillus and Lysinibacillus. Although the microbial community structure was significantly affected by the feedstock shift, the acidogenic and PHA storing performance of the 3-stage system was very similar once a pseudo steady state was attained, showing that a reliable level of functional redundancy was attained in both mixed cultures.
AB - Polyhydroxyalkanoates (PHA) are biopolymers that can be produced by mixed microbial cultures using wastes or industrial by-products, which represent an economical and environmental advantage over pure culture processes. The use of alternate feedstocks enables using seasonal by-products, providing that the process is resilient to transient conditions. The mixed microbial communities of a 3-stage PHA producing system fed initially with molasses and then cheese whey were investigated through amplicon sequencing of the 16S rRNA gene. The transition in feedstock resulted in an adaptation of the acidogenic community, where Actinobacteria dominated with sugarcane molasses (up to 93% of the operational taxonomic units) and Firmicutes, with cheese whey (up to 97%). The resulting fermentation products profile also changed, with a higher fraction of HV precursors obtained with molasses than cheese whey (7.1 ± 0.5 and 1.7 ± 0.7 gCOD/L, respectively). As for the PHA storing culture, the genera Azoarcus, Thauera and Paracoccus were enriched with fermented molasses (average 89% of Bacteria). Later, fermented cheese whey fostered a higher diversity, including some less characterised PHA-storers such as the genera Paenibacillus and Lysinibacillus. Although the microbial community structure was significantly affected by the feedstock shift, the acidogenic and PHA storing performance of the 3-stage system was very similar once a pseudo steady state was attained, showing that a reliable level of functional redundancy was attained in both mixed cultures.
KW - acidogenesis
KW - cheese whey
KW - functional redundancy
KW - Microbial ecology
KW - molasses
KW - polyhydroxyalkanoates (PHA)
UR - http://www.scopus.com/inward/record.url?scp=85028073766&partnerID=8YFLogxK
U2 - 10.1016/j.nbt.2017.08.007
DO - 10.1016/j.nbt.2017.08.007
M3 - Conference article
AN - SCOPUS:85028073766
SN - 1871-6784
VL - 40
SP - 207
EP - 217
JO - New Biotechnology
JF - New Biotechnology
IS - Part B
T2 - 9th Congress of the Spanish Federation of Biotechnologists/Annual Congress of Biotechnology (BAC)
Y2 - 8 July 2015 through 10 July 2015
ER -