Assessment of Protein-Rich Cheese Whey Waste Stream as a Nutrients Source for Low-Cost Mixed Microbial PHA Production
The critical step in the mixed microbial cultures (MMC) polyhydroxyalkanoates (PHA) production process is the selection of an MMC enriched in an efficient PHA-accumulating organism, usually requiring growth-nutrients supplementation. This study aimed at assessing cheese whey (CW) proteins as a sourc...
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doaj-62840590fd234cdea65c8452d3367ebb2020-11-25T01:27:25ZengMDPI AGApplied Sciences2076-34172018-10-01810181710.3390/app8101817app8101817Assessment of Protein-Rich Cheese Whey Waste Stream as a Nutrients Source for Low-Cost Mixed Microbial PHA ProductionCatarina S. S. Oliveira0Marisa O. D. Silva1Carlos E. Silva2Gilda Carvalho3Maria A. M. Reis4UCIBIO-REQUIMTE, Dep. Chemistry, Faculty of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, PortugalUCIBIO-REQUIMTE, Dep. Chemistry, Faculty of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, PortugalUCIBIO-REQUIMTE, Dep. Chemistry, Faculty of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, PortugalUCIBIO-REQUIMTE, Dep. Chemistry, Faculty of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, PortugalUCIBIO-REQUIMTE, Dep. Chemistry, Faculty of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, PortugalThe critical step in the mixed microbial cultures (MMC) polyhydroxyalkanoates (PHA) production process is the selection of an MMC enriched in an efficient PHA-accumulating organism, usually requiring growth-nutrients supplementation. This study aimed at assessing cheese whey (CW) proteins as a source of nitrogen for PHA-producing MMC, thus eliminating or reducing the need for nutrients supplementation. The selection reactor, operated with fermented CW, under a feast–famine regime, was initially supplemented with ammonia–nitrogen in a C/N ratio of 100/15 (Cmol/Nmmol), which was gradually reduced until eliminated, in order to select a culture capable of using CW proteins nitrogen. Decreasing nitrogen supplementation from a C/N ratio of 100/10 to 100/7.5 lead to significant microbial community changes, and reduced the MMC PHA-storing capacity, storage yield, and PHA productivity, decreasing by 30%, and over 45%, respectively. The PHA-storing capacity further deteriorated as nitrogen supplementation was reduced, despite increased protein-uptake. Results show that a culture enriched in PHA-accumulators capable of using proteins as sole nitrogen source could not be attained. In conclusion, this work reports for the first time that an easily bioavailable nitrogen source is required for efficiently selecting PHA-accumulating cultures. Based on the results obtained from this work, a pilot scale plant (two reactors of 100 L) fed with cheese whey for production of PHA is currently being successfully operated under the scope of the YPACK EU project, in which the selection reactor is supplemented with nitrogen (ammonia) from a total C/N ratio of 100/10.http://www.mdpi.com/2076-3417/8/10/1817proteinsmixed microbial cultures (MMC)cheese wheypolyhydroxyalkanoatesmicrobial characterisationnitrogen source |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Catarina S. S. Oliveira Marisa O. D. Silva Carlos E. Silva Gilda Carvalho Maria A. M. Reis |
spellingShingle |
Catarina S. S. Oliveira Marisa O. D. Silva Carlos E. Silva Gilda Carvalho Maria A. M. Reis Assessment of Protein-Rich Cheese Whey Waste Stream as a Nutrients Source for Low-Cost Mixed Microbial PHA Production Applied Sciences proteins mixed microbial cultures (MMC) cheese whey polyhydroxyalkanoates microbial characterisation nitrogen source |
author_facet |
Catarina S. S. Oliveira Marisa O. D. Silva Carlos E. Silva Gilda Carvalho Maria A. M. Reis |
author_sort |
Catarina S. S. Oliveira |
title |
Assessment of Protein-Rich Cheese Whey Waste Stream as a Nutrients Source for Low-Cost Mixed Microbial PHA Production |
title_short |
Assessment of Protein-Rich Cheese Whey Waste Stream as a Nutrients Source for Low-Cost Mixed Microbial PHA Production |
title_full |
Assessment of Protein-Rich Cheese Whey Waste Stream as a Nutrients Source for Low-Cost Mixed Microbial PHA Production |
title_fullStr |
Assessment of Protein-Rich Cheese Whey Waste Stream as a Nutrients Source for Low-Cost Mixed Microbial PHA Production |
title_full_unstemmed |
Assessment of Protein-Rich Cheese Whey Waste Stream as a Nutrients Source for Low-Cost Mixed Microbial PHA Production |
title_sort |
assessment of protein-rich cheese whey waste stream as a nutrients source for low-cost mixed microbial pha production |
publisher |
MDPI AG |
series |
Applied Sciences |
issn |
2076-3417 |
publishDate |
2018-10-01 |
description |
The critical step in the mixed microbial cultures (MMC) polyhydroxyalkanoates (PHA) production process is the selection of an MMC enriched in an efficient PHA-accumulating organism, usually requiring growth-nutrients supplementation. This study aimed at assessing cheese whey (CW) proteins as a source of nitrogen for PHA-producing MMC, thus eliminating or reducing the need for nutrients supplementation. The selection reactor, operated with fermented CW, under a feast–famine regime, was initially supplemented with ammonia–nitrogen in a C/N ratio of 100/15 (Cmol/Nmmol), which was gradually reduced until eliminated, in order to select a culture capable of using CW proteins nitrogen. Decreasing nitrogen supplementation from a C/N ratio of 100/10 to 100/7.5 lead to significant microbial community changes, and reduced the MMC PHA-storing capacity, storage yield, and PHA productivity, decreasing by 30%, and over 45%, respectively. The PHA-storing capacity further deteriorated as nitrogen supplementation was reduced, despite increased protein-uptake. Results show that a culture enriched in PHA-accumulators capable of using proteins as sole nitrogen source could not be attained. In conclusion, this work reports for the first time that an easily bioavailable nitrogen source is required for efficiently selecting PHA-accumulating cultures. Based on the results obtained from this work, a pilot scale plant (two reactors of 100 L) fed with cheese whey for production of PHA is currently being successfully operated under the scope of the YPACK EU project, in which the selection reactor is supplemented with nitrogen (ammonia) from a total C/N ratio of 100/10. |
topic |
proteins mixed microbial cultures (MMC) cheese whey polyhydroxyalkanoates microbial characterisation nitrogen source |
url |
http://www.mdpi.com/2076-3417/8/10/1817 |
work_keys_str_mv |
AT catarinassoliveira assessmentofproteinrichcheesewheywastestreamasanutrientssourceforlowcostmixedmicrobialphaproduction AT marisaodsilva assessmentofproteinrichcheesewheywastestreamasanutrientssourceforlowcostmixedmicrobialphaproduction AT carlosesilva assessmentofproteinrichcheesewheywastestreamasanutrientssourceforlowcostmixedmicrobialphaproduction AT gildacarvalho assessmentofproteinrichcheesewheywastestreamasanutrientssourceforlowcostmixedmicrobialphaproduction AT mariaamreis assessmentofproteinrichcheesewheywastestreamasanutrientssourceforlowcostmixedmicrobialphaproduction |
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