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Jiang M, Wang P, Liu H, Dai X, Song S, Liu Y. The Effect of Operating Strategies on the Anaerobic Digestion of Gentamicin Mycelial Residues: Insights into the Enhancement of Methane Production and Attenuation of Gentamicin Resistance. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15130-15140. [PMID: 35984723 DOI: 10.1021/acs.est.2c00481] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Anaerobic digestion (AD) has been widely employed for converting various biowastes into renewable energy. However, AD of gentamicin mycelial residues (GMRs, a byproduct of gentamicin production) is limited by ammonia inhibition and antimicrobial resistance risk. Compared to mesophilic AD (MMAD) of GMRs, this study looked into three semicontinuous AD processes, i.e., codigestion with wheat straw, thermophilic digestion (TAcoD), and AD at shortened retention time (RT). Results showed that a stable and safe AD could be achieved under suitable operating conditions. Co-digestion could effectively mitigate the adverse effect of ammonia inhibition. The methane production increased by 35.86% in TAcoD compared to that in MMAD and 43.99% of hazardous waste was reduced in TAcoD. Concerning the antimicrobial resistance of AD system, gentamicin was degraded efficiently and the degradation process was not involved in the expression of antibiotic resistance genes (ARGs) related to modifying enzyme. Effective removal of ARGs under three operating strategies was associated with a higher reduction in bacterial abundance of potential hosts. In addition, the changes in the relevant proteins for transformation and conjugation as predicted by PICRUSt suggested that thermophilic condition and shorter RT were conducive to the reduction of the dissemination risks of ARGs.
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Affiliation(s)
- Mingye Jiang
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Peng Wang
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Huiling Liu
- School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xiaohu Dai
- School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Siqi Song
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Yu Liu
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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Jiang M, Song S, Liu H, Dai X, Wang P. Responses of methane production, microbial community and antibiotic resistance genes to the mixing ratio of gentamicin mycelial residues and wheat straw in anaerobic co-digestion process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150488. [PMID: 34607101 DOI: 10.1016/j.scitotenv.2021.150488] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 09/16/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Anaerobic co-digestion (AcoD) of gentamicin mycelial residues (GMRs), a kind of nitrogen-rich biowaste, and wheat straw (WS) is an attractive technology for the recycling of GMRs. However, the effects of the co-substrate ratio on methane production, system stability and antimicrobial resistance during co-digestion remain unclear. Thus, this study aimed to fill in the blanks through AcoD of GMRs and WS with different mixing ratios (1:0, 2:1, 1:1, 1:2, 0:1, VS basis) via batch tests. Results showed that AcoD facilitated methane production than mono anaerobic digestion and reduced the accumulation of the toxic substances, such as ammonia nitrogen and humic-like substances. The maximum methane production was obtained at the reactors with the mixing ratio of 1:1 and 1:2 (R-1:1 and R-1:2), which matched with the relative abundance of key enzymes related to methanogenesis predicted by PICRUSt. Microbial community analysis indicated that Methanosaeta was the most dominant methanogen in the AcoD reactors. The highest relative abundance of Methanosaeta (45.1%) was obtained at R-1:1 due to the appropriate AcoD conditions, thus, providing greater possibilities for high stability of AcoD system. Additionally, AcoD of the GMRs and WS under the mixing ratio of 1:1 and 1:2 did not prompt the increase of antibiotic resistance genes (ARGs). Not only that, the likelihood of horizontal gene transfer declined in R-1:1 due to the weaker connection and transport between host and recipient bacteria. Findings of this study suggested that the suitable mixing ratio of GMRs and WS contributes to methane production and system stability, and reduces the dissemination risks of ARGs.
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Affiliation(s)
- Mingye Jiang
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Siqi Song
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Huiling Liu
- School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
| | - Xiaohu Dai
- School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Peng Wang
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China.
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Huang Q, Liu Y, Dhar BR. Pushing the organic loading rate in electrochemically assisted anaerobic digestion of blackwater at ambient temperature: Insights into microbial community dynamics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 781:146694. [PMID: 33812109 DOI: 10.1016/j.scitotenv.2021.146694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/17/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Decentralized blackwater treatment by anaerobic digestion is being considered as a sustainable sanitation concept. However, the low biodegradability and complex composition restrictedly limited the treatability of blackwater, resulting in requirements of low operational organic loading rates (OLRs). In this study, a microbial electrolysis cell assisted anaerobic digester (MEC-AD) treating vacuum toilet blackwater was successfully operated for 420 days at OLRs ranging from 0.77 to 3.03 g COD/L-d in 6 stages (including an open-circuit Stage 5) at ambient temperature. Based on the steady-state results from different stages, the highest methane yield (42.4% out of 45% biochemical methane potential value) was achieved in Stage 1 with an OLR of 0.77 g COD/L-d. At the same OLR of ~3.0 g COD/L-d, Stage 4 (32.4%) and Stage 6 (35.2%) showed significantly higher methane yield (p < 0.01) than open-circuit Stage 5 (24.1%). The lowest COD removal efficiency of 31.8% was observed in Stage 5 with short-chain volatile fatty acids (SCVFAs) accumulated to ~1000 mg/L, which was more than double the values of Stage 4 and 6. The microbial community analysis revealed that the applied potential did not significantly affect archaeal diversity but largely increased the archaeal abundance on the cathode, and led the bacterial community shift with the enrichment of specific electroactive bacteria. Microbial co-occurrence network analysis further confirmed the positive correlations between known electroactive bacteria and electrotrophic methanogens. Moreover, electric energy consumed by the MEC-AD system was fully recovered as biomethane.
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Affiliation(s)
- Qi Huang
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
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Du G, Zhang G, Shi J, Zhang J, Ma Z, Liu X, Yuan C, Li X, Zhang B. Keystone Taxa Lactiplantibacillus and Lacticaseibacillus Directly Improve the Ensiling Performance and Microflora Profile in Co-Ensiling Cabbage Byproduct and Rice Straw. Microorganisms 2021; 9:microorganisms9051099. [PMID: 34065243 PMCID: PMC8161039 DOI: 10.3390/microorganisms9051099] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/09/2021] [Accepted: 05/13/2021] [Indexed: 02/02/2023] Open
Abstract
Ensiling has been widely applied to cope with agricultural solid waste to achieve organic waste valorization and relieve environmental pressure and feedstuff shortage. In this study, co-ensiling of cabbage leaf byproduct and rice straw was performed with inoculation of Lactiplantibacillusplantarum (LP) to investigate the effects of inoculation on ensiling performance and microflora profiles. Compared to the control, LP inoculation preserved more dry matter (DM) content (283.4 versus 270.9 g·kg-1 fresh matter (FM) on day 30), increased lactic acid (LA) content (52.1 versus 35.8 g·kg-1 dry matter on day 15), decreased pH (3.55 versus 3.79 on day 15), and caused accumulation of acetic acid (AA), butyric acid (BA), and ammonia. The investigation showed that LP inoculation modified microflora composition, especially resisting potential pathogens and enriching more lactic acid bacteria (LAB) (p < 0.05). Moreover, Lactiplantibacillus and Lacticaseibacillus were identified as the keystone taxa that influenced physicochemical properties and interactions in microflora. They were also the main functional species that directly restrained undesirable microorganisms (p < 0.05), rather than indirectly working via metabolite inhibition and substrate competition (p > 0.05). The results of this present study improve the understanding of the underlying effect of LP inoculation on improving silage quality and facilitate the bio-transformation of cabbage byproduct and rice straw as animal feed.
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Affiliation(s)
- Guilin Du
- Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Pudong, Shanghai 201210, China; (G.D.); (J.S.); (J.Z.); (Z.M.); (X.L.); (C.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
| | - Guilong Zhang
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China;
| | - Jiping Shi
- Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Pudong, Shanghai 201210, China; (G.D.); (J.S.); (J.Z.); (Z.M.); (X.L.); (C.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
| | - Jingxian Zhang
- Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Pudong, Shanghai 201210, China; (G.D.); (J.S.); (J.Z.); (Z.M.); (X.L.); (C.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiguo Ma
- Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Pudong, Shanghai 201210, China; (G.D.); (J.S.); (J.Z.); (Z.M.); (X.L.); (C.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangcen Liu
- Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Pudong, Shanghai 201210, China; (G.D.); (J.S.); (J.Z.); (Z.M.); (X.L.); (C.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chenyang Yuan
- Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Pudong, Shanghai 201210, China; (G.D.); (J.S.); (J.Z.); (Z.M.); (X.L.); (C.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
| | - Xiang Li
- Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Pudong, Shanghai 201210, China; (G.D.); (J.S.); (J.Z.); (Z.M.); (X.L.); (C.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (X.L.); (B.Z.); Tel.: +86-18202130394 (X.L.); +86-21-20325161 (B.Z.); Fax: +86-21-20325173 (X.L. & B.Z.)
| | - Baoguo Zhang
- Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Pudong, Shanghai 201210, China; (G.D.); (J.S.); (J.Z.); (Z.M.); (X.L.); (C.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (X.L.); (B.Z.); Tel.: +86-18202130394 (X.L.); +86-21-20325161 (B.Z.); Fax: +86-21-20325173 (X.L. & B.Z.)
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