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Perez-Esteban N, Vives-Egea J, Peces M, Dosta J, Astals S. Temperature-driven carboxylic acid production from waste activated sludge and food waste: Co-fermentation performance and microbial dynamics. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 178:176-185. [PMID: 38401431 DOI: 10.1016/j.wasman.2024.02.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/20/2024] [Accepted: 02/16/2024] [Indexed: 02/26/2024]
Abstract
This work aims to improve the continuous co-fermentation of waste activated sludge (WAS) and food waste (FW) by investigating the long-term impact of temperature on fermentation performance and the underpinning microbial community. Acidogenic co-fermentation of WAS and FW (70:30 % VS-basis) to produce volatile fatty acids (VFA) was studied in continuous fermenters at different temperatures (25, 35, 45, 55 °C) at an organic loading rate of 11 gVS/(L·d) and a hydraulic retention time of 3.5 days. Two batches of WAS (A and B) were collected from the same wastewater treatment plant at different periods to understand the impact of the WAS microbioota on the fermenters' microbial communities. Solubilisation yield was higher at 45 °C (575 ± 68 mgCOD/gVS) followed by 55 °C (508 ± 45 mgCOD/gVS). Fermentation yield was higher at 55 °C (425 ± 28 mgCOD/gVS) followed by 35 °C (327 ± 17 mgCOD/gVS). Temperature also had a noticeable impact on the VFA profile. At 55 °C, acetic (40 %) and butyric (40 %) acid dominated, while acetic (37 %), butyric acid (31 %), and propionic acid (17 %) dominated at 35 °C. At 45 °C, an accumulation of caproic acid was detected which did not occur at other temperatures. Each temperature had a distinct microbial community, where the WAS microbiota played an important role. The biomass mass-balance showed the highest growth of microorganisms (51 %) at 35 °C and WAS_B, where a consumption of acetic acid was observed. Therefore, at 35 °C, there is a higher risk of acetic acid consumption probably due to the proliferation of methanogens imported from WAS.
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Affiliation(s)
- N Perez-Esteban
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - J Vives-Egea
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - M Peces
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - J Dosta
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - S Astals
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
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Hu Z, Wang C, Pan L, Han S, Jin M, Xiang Y, Zheng L, Li Z, Cao R, Qin B. Identification and a phased pH control strategy of diosgenin bio-synthesized by an endogenous Bacillus licheniformis Syt1 derived from Dioscorea zingiberensis C. H. Wright. Appl Microbiol Biotechnol 2021; 105:9333-9342. [PMID: 34841464 DOI: 10.1007/s00253-021-11679-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/07/2021] [Accepted: 11/02/2021] [Indexed: 11/28/2022]
Abstract
Diosgenin is widely used as one precursor of steroidal drugs in pharmaceutical industry. Currently, there is no choice but to traditionally extract diosgenin from Dioscorea zingiberensis C. H. Wright (DZW) or other plants. In this work, an environmentally friendly approach, in which diosgenin can be bio-synthesized by the endophytic bacterium Bacillus licheniformis Syt1 isolated from DZW, is proposed. Diosgenin produced by the strain was identified by high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FTIR). The thermal gravimetric analysis (TGA) showed that the melting point of the diosgenin product was 204 °C. The optical rotation measurement exhibited that the optical rotation was α20589 = - 126.1° ± 1.5° (chloroform, c = 1%): negative sign means that the product is left-handed, which is very important to further produce steroid hormone drugs. Cholesterol may be the intermediate product in the diosgenin biosynthesis pathway. In the batch fermentation process to produce diosgenin using the strain, pH values played an important role. A phased pH control strategy from 5.5 to 7.5 was proved to be more effective to improve production yield than any single pH control, which could get the highest diosgenin yield of 85 ± 8.6 mg L-1. The proposed method may replace phyto-chemistry extraction to produce diosgenin in the industry in the future.Key points• An endophytic Bacillus licheniformis Syt1 derived from host can produce diosgenin.• A dynamic pH industrial control strategy is better than any single pH control.• Proposed diosgenin-produced method hopefully replaces phyto-chemistry extraction.
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Affiliation(s)
- Zhongqiu Hu
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Chunli Wang
- YangLing Demonstration Zone Hospital, Yangling, Shaanxi, 712100, People's Republic of China
| | - Lintao Pan
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Shiyao Han
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Miao Jin
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Yongsheng Xiang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Lifei Zheng
- College of Science, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Zhonghong Li
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Rang Cao
- College of Grassland Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Baofu Qin
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
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