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Cao X, Cai R, Zuo S, Niu D, Yang F, Xu C. Enhanced lignin degradation by Irpex lacteus through expanded sterilization further improved the fermentation quality and microbial community during the silage preservation process. BIORESOUR BIOPROCESS 2024; 11:14. [PMID: 38647879 PMCID: PMC10992542 DOI: 10.1186/s40643-024-00730-2] [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: 11/12/2023] [Accepted: 01/10/2024] [Indexed: 04/25/2024] Open
Abstract
Traditional autoclaving, slow degradation rate and preservation of biomass treated by fungi are the main factors restricting biological treatment. In our previous studies, strains with high efficiency and selective lignin degradation ability were obtained. To further solve the limiting factors of biological treatment, this paper proposed a composite treatment technology, which could replace autoclaves for fungal treatment and improve the preservation and utilization of fungal-pretreated straw. The autoclaved and expanded buckwheat straw were, respectively, degraded by Irpex lacteus for 14 days (CIL, EIL), followed by ensiling of raw materials (CK) and biodegraded straw of CIL and EIL samples with Lactobacillus plantarum for different days, respectively (CP, CIP, EIP). An expansion led to lactic acid bacteria, mold, and yeast of the samples below the detection line, and aerobic bacteria was significantly reduced, indicating a positive sterilization effect. Expansion before I. lacteus significantly enhanced lignin selective degradation by about 6%, and the absolute content of natural detergent solute was about 5% higher than that of the CIL. Moreover, EIL decreased pH by producing higher organic acids. The combination treatment created favorable conditions for ensiling. During ensiling, EIP silage produced high lactic acid about 26.83 g/kg DM and the highest acetic acid about 22.35 g/kg DM, and the pH value could be stable at 4.50. Expansion before I. lacteus optimized the microbial community for ensiling, resulting in EIP silage co-dominated by Lactobacillus, Pediococcus and Weissella, whereas only Lactobacillus was always dominant in CP and CIP silage. Clavispora gradually replaced Irpex in EIP silage, which potentially promoted lactic acid bacteria growth and acetic acid production. In vitro gas production (IVGP) in EIL was increased by 30% relative to CK and was higher than 24% in CIL. The role of expansion was more significant after ensiling, the IVGP in EIP was increased by 22% relative to CP, while that in CIP silage was only increased by 9%. Silage of fungal-treated samples reduced methane emissions by 28% to 31%. The study demonstrated that expansion provides advantages for fungal colonization and delignification, and further improves the microbial community and fermentation quality for silage, enhancing the nutrition and utilization value. This has practical application value for scaling up biological treatment and preserving the fungal-treated lignocellulose.
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Affiliation(s)
- Xiaohui Cao
- College of Engineering, China Agricultural University, (East Campus), 17 Qing-Hua-Dong-Lu, Haidian District, Beijing, 100083, People's Republic of China
| | - Rui Cai
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, Hubei Province, China
| | - Sasa Zuo
- College of Engineering, China Agricultural University, (East Campus), 17 Qing-Hua-Dong-Lu, Haidian District, Beijing, 100083, People's Republic of China
| | - Dongze Niu
- Changzhou Key Laboratory of Biomass Green, Safe and High Value Utilization Technology, Institute of Urban and Rural Mining, Changzhou University, Changzhou, 213164, China
| | - Fuyu Yang
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100093, People's Republic of China
| | - Chuncheng Xu
- College of Engineering, China Agricultural University, (East Campus), 17 Qing-Hua-Dong-Lu, Haidian District, Beijing, 100083, People's Republic of China.
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Niu D, Zhu P, Pan T, Yu C, Li C, Ren J, Xu C. Ensiling Improved the Colonization and Degradation Ability of Irpex lacteus in Wheat Straw. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:13668. [PMID: 36294244 PMCID: PMC9603578 DOI: 10.3390/ijerph192013668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/30/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
To develop a non-thermal method to replace steam autoclaving for white-rot fungi fermentation, Irpex lacteus spawn was inoculated in wheat straw (WSI) or ensiled WS (WSI) at varying ratios of 10%, 20%, 30%, 40%, and 50%, and incubated at 28 °C for 28 days to determine the effects of the ensiling and inoculation ratio on the colonization and degradation ability of Irpex lacteus in wheat straw (WS). The results demonstrate that ensiling effectively inhibited the growth of aerobic bacteria and molds, as well as other harmful microorganisms in WS, which created a favorable condition for the growth of I. lacteus. After the treatment of I. lacteus, the pH of EWSI decreased to below 5, while that of WSI, except for the feedstocks of WSI-50%, was around 7, indicating that I. lacteus colonized well in the ensiled WS because the substrates dominated by I. lacteus are generally acidic. Correspondingly, except for the molds in WSI-50% samples, the counts of other microorganisms in WSI, such as aerobic bacteria and molds, were significantly higher than those in EWSI (p < 0.05), indicating that contaminant microorganisms had a competitive advantage in non-ensiled substrates. Incubation with I. lacteus did not significantly affect the cellulose content of all samples. However, the NDS content of EWSI was significantly higher than that of WSI (p < 0.05), and the hemicellulose and lignin contents were significantly lower than the latter (p < 0.05), except for the NDS and hemicellulose contents of WSI-50% samples. Correlation analysis revealed a stronger negative correlation between NDS content and the contents of hemicellulose, cellulose, and lignin in EWSI, which could be caused by the destruction of lignin and hemicellulose and the conversion from structural carbohydrates to fungal polysaccharides or other compounds in NDS form. Even for WSI-50% samples, the sugar yield of WS treated with I. lacteus improved with an increasing inoculation ratio, but the ratio was not higher than that of the raw material. However, the sugar yield of EWSI increased by 51-80%, primarily owing to the degradation of lignin and hemicellulose. Above all, ensiling improves the colonization ability of I. lacteus in WS, which promotes the degradation of lignin and hemicellulose and the enzymic hydrolysis of cellulose, so combining ensiling and I. lacteus fermentation has promising potential in the pretreatment of WS.
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Affiliation(s)
- Dongze Niu
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization, National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization, Institute of Urban and Rural Mining, Changzhou University, Changzhou 213164, China
- College of Engineering, China Agricultural University, Beijing 100083, China
| | - Peng Zhu
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization, National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization, Institute of Urban and Rural Mining, Changzhou University, Changzhou 213164, China
- School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Tingting Pan
- College of Engineering, China Agricultural University, Beijing 100083, China
- Shandong Institute of Standardization, Jinan 250014, China
| | - Changyong Yu
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization, National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization, Institute of Urban and Rural Mining, Changzhou University, Changzhou 213164, China
- School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Chunyu Li
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization, National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization, Institute of Urban and Rural Mining, Changzhou University, Changzhou 213164, China
| | - Jianjun Ren
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization, National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization, Institute of Urban and Rural Mining, Changzhou University, Changzhou 213164, China
| | - Chuncheng Xu
- College of Engineering, China Agricultural University, Beijing 100083, China
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Niu D, Yu C, Zheng M, Ren J, Li C, Xu C. Effects of ensiling on Irpex lacteus fermentation in wheat straw: Chemical composition, in vitro rumen digestibility, and fungal community. Anim Feed Sci Technol 2022. [DOI: 10.1016/j.anifeedsci.2022.115433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Ensiling with rumen fluid promoted Irpex lacteus colonization on the non-sterile naked oat straw for enhanced lignocellulose degradation and enzymatic hydrolysis. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108462] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Vasco-Correa J, Capouya R, Shah A, Mitchell TK. Sequential fungal pretreatment of unsterilized Miscanthus: changes in composition, cellulose digestibility and microbial communities. Appl Microbiol Biotechnol 2022; 106:2263-2279. [PMID: 35171342 DOI: 10.1007/s00253-022-11833-1] [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: 09/02/2021] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 11/30/2022]
Abstract
A sequential fungal pretreatment of Miscanthus × giganteus was conducted by mixing unsterilized Miscanthus with material previously colonized with the white-rot fungus Ceriporiopsis subvermispora. For three generations, each generation started with inoculation by mixing unsterilized fresh Miscanthus with end material from the previous generation and ended after 28 days of incubation at 28 °C. After the first generation, the cellulose digestibility of the material doubled, compared to that of the unsterilized Miscanthus, but the second and third generations showed no enhancements in cellulose digestibility. Furthermore, high degradation of Miscanthus structural carbohydrates occurred during the first generation. A microbial community study showed that, even though the fungal community of the material previously colonized by C. subvermispora was composed mainly of this fungus (> 99%), by the first generation its relative abundance was down to only 9%, and other microbes had prevailed. Additionally, changes in the bacterial community occurred that might be associated with unwanted cellulose degradation in the system. This reiterates the necessity of feedstock microbial load reduction for the stability and reproducibility of fungal pretreatment of lignocellulosic biomass. KEY POINTS: • Sequential fungal pretreatment of unsterilized Miscanthus was unsuccessful. • Feedstock changes with white-rot fungi favored the growth of other microorganisms. • Feedstock microbial reduction is necessary for pretreatment with C. subvermispora.
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Affiliation(s)
- Juliana Vasco-Correa
- Department of Food, Agricultural and Biological Engineering, The Ohio State University/Ohio Agricultural Research and Development Center, Wooster, OH, 44691, USA. .,Department of Agricultural and Biological Engineering, Penn State University, University Park, PA, 16802, USA.
| | - Rachel Capouya
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210, USA
| | - Ajay Shah
- Department of Food, Agricultural and Biological Engineering, The Ohio State University/Ohio Agricultural Research and Development Center, Wooster, OH, 44691, USA
| | - Thomas K Mitchell
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210, USA
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Zheng M, Li R, Wang Y, Yang F, Xu C. An efficient strategy to improve enzymatic hydrolysis of naked oat straw pretreated by Irpex lacteus. Bioprocess Biosyst Eng 2021; 45:227-236. [PMID: 34626233 DOI: 10.1007/s00449-021-02652-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/03/2021] [Indexed: 11/29/2022]
Abstract
The objective of this study was aiming at developing an efficient strategy to promote enzymatic hydrolysis of naked oat straw and deciphering the potential mechanism. Irpex lacteus and Phlebia acerina were employed to inoculated on the naked oat straw for 4 weeks which the changes of fiber components, fermentation losses, lignin-degrading enzymes production pattern were determined weekly. Furthermore, the 72 h enzymatic hydrolysis of ultimately fermented naked oat straw were also evaluated. The acid detergent lignin was degraded at about 25% along with the moderate dry matter and cellulose loss which both showed selective degradation. The lignin-degrading enzymes production patterns of the two fungi were different which lignin peroxidase was not detected in Irpex lacteus treatment. In addition, the activities of cellulolytic enzymes were higher in Phlebia acerina treatment. After 72 h enzymatic hydrolysis, the reducing sugar content and hydrolysis yield pretreated by Irpex lacteus was 12.92 g/L and 69.49%, respectively. It was much higher than that in sterilized substrate and Phlebia acerina treatment. Meanwhile, the hydrolysis yields of glucose, sum of xylose and arabinose were all improved by Irpex lacteus which were 30.96% and 25.62%, respectively, and showed significant enhancements compared to control and Phlebia acerina treatment. Irpex lacteus is one of effective white rot fungi which could promote the enzymatic hydrolysis of naked oat straw obviously.
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Affiliation(s)
- Menghu Zheng
- College of Engineering, China Agricultural University, No. 17 Qinghua Donglu, Haidian District, Beijing, 100083, China
| | - Rongrong Li
- College of Engineering, China Agricultural University, No. 17 Qinghua Donglu, Haidian District, Beijing, 100083, China
| | - Yan Wang
- College of Engineering, China Agricultural University, No. 17 Qinghua Donglu, Haidian District, Beijing, 100083, China
| | - Fuyu Yang
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100093, China
| | - Chuncheng Xu
- College of Engineering, China Agricultural University, No. 17 Qinghua Donglu, Haidian District, Beijing, 100083, China.
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