1
|
Agyeman-Duah E, Okonkwo CC, Ujor VC. Microbial removal of nutrients from anaerobic digestate: assessing product-coupled and non-product-coupled approaches. Front Microbiol 2023; 14:1299402. [PMID: 38146449 PMCID: PMC10749329 DOI: 10.3389/fmicb.2023.1299402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/27/2023] [Indexed: 12/27/2023] Open
Abstract
Although anaerobic digestate contains >90% water, the high nutrient content of digestate makes it economically and technically intractable to treatment by existing wastewater treatment technologies. This study separately assessed the feasibility of nutrient removal from digestate by Rhizopus delemar DSM 905 and a culture of phosphate-accumulating organisms (PAOs). With Rhizopus delemar DSM 905, we investigated concomitant nutrient removal from digestate-supplemented medium and fumaric acid production, as a potentially economical strategy for digestate treatment. Following the cultivation of R. delemar DSM 905 in a fermentation medium containing 25% (v/v) digestate, the concentrations of Al, Cr, Cu, Fe, K, Mg, Mn, Pb, and Zn reduced 40, 12, 74, 96, 12, 26, 23%, ~18, and 28%, respectively. Similarly, the concentrations of total phosphorus, total nitrogen, phosphate (PO4-P), ammonium (NH4-N), nitrate (NO3-N), and sulfur decreased 93, 88, 97, 98, 69, and 13%, respectively. Concomitantly, cultures supplemented with 25 and 15% (v/v) digestate produced comparable titers of fumarate (~11 and ~ 17 g/L, respectively) to the digestate un-supplemented control cultures. With PAOs, we assessed the removal of total phosphorus, total nitrogen, PO4-P, and NH4-N, of which the concentrations reduced 86, 90%, ~99, and 100%, respectively in 60% (v/v) digestate. This study provides additional bases for microbial removal of excess nutrients from anaerobic digestate, with the potential to engender future water recovery from this waste stream that is currently largely recalcitrant to treatment.
Collapse
Affiliation(s)
- Eric Agyeman-Duah
- Fermentation Science and Metabolic Engineering Group, Department of Food Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Christopher C. Okonkwo
- Biotechnology Program, Department of Chemistry and Chemical Biology, The Roux Institute, Northeastern University, Portland, ME, United States
| | - Victor C. Ujor
- Fermentation Science and Metabolic Engineering Group, Department of Food Science, University of Wisconsin-Madison, Madison, WI, United States
| |
Collapse
|
2
|
Kintl A, Vítěz T, Huňady I, Sobotková J, Hammerschmiedt T, Vítězová M, Brtnický M, Holátko J, Elbl J. Effect of Mycotoxins in Silage on Biogas Production. Bioengineering (Basel) 2023; 10:1387. [PMID: 38135978 PMCID: PMC10740816 DOI: 10.3390/bioengineering10121387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/22/2023] [Accepted: 11/26/2023] [Indexed: 12/24/2023] Open
Abstract
Mycotoxins can pose a threat to biogas production as they can contaminate the feedstock used in biogas production, such as agricultural crops and other organic materials. This research study evaluated the contents of deoxynivalenol (DON), zearalenone (ZEA), fumonisin (FUM), and aflatoxin (AFL) mycotoxins in maize silage prior to it being processed in a biogas plant and in digestate produced at the end of the anaerobic digestion (AD) process. In the experiment, three samples of silage were collected from one silage warehouse: Variant 1 = low contamination, Variant 2 = medium contamination, and Variant 3 = heavy contamination, which were subjected to investigation. A significantly reduced biogas production was recorded that was proportional to the increasing contamination with molds, which was primarily due to the AD of silage caused by technologically erroneous silage treatment. The AD was connected with changes in silage composition expressed by the values of VS content, sugar content, lactic acid content, acetic acid content, and the ratio of lactic acid content to acetic acid content. The production of biogas and methane decreased with the increasing contents of NDF, ADF, CF, and lignin. The only exception was Variant 2, in which the content of ADF, CF, and lignin was lower (by 8-11%) than that in Variant 1, and only the content of NDF was higher (by 9%) than that in Variant 1. A secondary factor that also correlated with changes in the composition of the substrate was the development of undesirable organisms, which further contributed to its degradation and to the production of mycotoxins. It was also demonstrated in this study that during the AD process, the tested mycotoxins were degraded, and their content was reduced by 27-100%. Only the variant with low mold contamination showed a DON concentration increase of 27.8%.
Collapse
Affiliation(s)
- Antonín Kintl
- Agricultural Research, Ltd., Zahradní 1, 664 41 Troubsko, Czech Republic; (A.K.); (I.H.); (J.S.)
| | - Tomáš Vítěz
- Department of Agricultural, Food and Environmental Engineering, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic
- Department of Experimental Biology, Section of Microbiology, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic;
| | - Igor Huňady
- Agricultural Research, Ltd., Zahradní 1, 664 41 Troubsko, Czech Republic; (A.K.); (I.H.); (J.S.)
| | - Julie Sobotková
- Agricultural Research, Ltd., Zahradní 1, 664 41 Troubsko, Czech Republic; (A.K.); (I.H.); (J.S.)
| | - Tereza Hammerschmiedt
- Department of Agrochemistry, Soil Science, Microbiology and Plant Nutrition, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic; (T.H.); (M.B.); (J.H.)
| | - Monika Vítězová
- Department of Experimental Biology, Section of Microbiology, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic;
| | - Martin Brtnický
- Department of Agrochemistry, Soil Science, Microbiology and Plant Nutrition, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic; (T.H.); (M.B.); (J.H.)
| | - Jiří Holátko
- Department of Agrochemistry, Soil Science, Microbiology and Plant Nutrition, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic; (T.H.); (M.B.); (J.H.)
- Agrovyzkum Rapotin, Ltd., Vyzkumniku 267, 788 13 Rapotin, Czech Republic
| | - Jakub Elbl
- Agricultural Research, Ltd., Zahradní 1, 664 41 Troubsko, Czech Republic; (A.K.); (I.H.); (J.S.)
- Department of Agrosystems and Bioclimatology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic
| |
Collapse
|
4
|
Repurposing anaerobic digestate for economical biomanufacturing and water recovery. Appl Microbiol Biotechnol 2022; 106:1419-1434. [PMID: 35122155 DOI: 10.1007/s00253-022-11804-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/18/2022] [Accepted: 01/23/2022] [Indexed: 11/02/2022]
Abstract
Due to mounting impacts of climate change, particularly increased incidence of drought, hence water scarcity, it has become imperative to develop new technologies for recovering water from nutrient-rich, water-replete effluents other than sewage. Notably, anaerobic digestate could be harnessed for the purpose of water recovery by repurposing digestate-borne minerals as nutrients in fermentative processes. The high concentrations of ammonium, phosphate, sulfate, and metals in anaerobic digestate are veritable microbial nutrients that could be harnessed for bio-production of bulk and specialty chemicals. Tethering nutrient sequestration from anaerobic digestate to bio-product accumulation offers promise for concomitant water recovery, bio-chemical production, and possible phosphate recovery. In this review, we explore the potential of anaerobic digestate as a nutrient source and as a buffering agent in fermentative production of glutamine, glutamate, fumarate, lactate, and succinate. Additionally, we discuss the potential of synthetic biology as a tool for enhancing nutrient removal from anaerobic digestate and for expanding the range of products derivable from digestate-based fermentations. Strategies that harness the nutrients in anaerobic digestate with bio-product accumulation and water recovery could have far-reaching implications on sustainable management of nutrient-rich manure, tannery, and fish processing effluents that also contain high amounts of water. KEY POINTS: • Anaerobic digestate may serve as a source of nutrients in fermentation. • Use of digestate in fermentation would lead to the recovery of valuable water.
Collapse
|