Continuous volatile fatty acid production from lignocellulosic biomass by a novel rumen-mimetic bioprocess

Agematu, Hitosi; Takahashi, Takehiko; Hamano, Yoshio

doi:10.1016/j.jbiosc.2017.06.006

Cited by 27 publications

(18 citation statements)

References 30 publications

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“…This topic has been frequently investigated (Mathews et al 2016;Agematu et al 2017) and the feasibility of a fungal pretreatment as an alternative to physical and chemical cellulose conversion has been described (Keller et al 2003;Bak et al 2009;Shi et al 2009;Xu et al 2009;Dias et al 2010;Sindhu et al 2016). The challenges of an industrial application are the long pretreatment time and the substantial loss of cellulose and hemicelluloses (Balan 2014), and the optimization of the cultivation conditions and sugar yields (Kumar et al 2008;Wan and Li 2012).…”

Section: Introductionmentioning

confidence: 99%

Cellulolytic activity of brown-rot Antrodia sinuosa at the initial stage of cellulose degradation

et al. 2019

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The initial stage of cellulose degradation has been studied via in vitro assays of fungi isolated from rotten wood in a boreal forest. Among the 37 isolates, Antrodia sinuosa appeared to be an effective cellulose degrader and was selected for studying the initial degradation process. In the liquid cultivation with carboxymethylcellulose (CMC), the increase of the mycelial dry weight coincided with the pH decrease of the culture medium from pH 5.7 to 3.9, between the 3rd and 6th cultivation day. At the same time, the cellulolytic activity increased; the CMCase activity increased sharply and the reducing sugars reached their maximum concentration in the culture medium. It seems that the decreasing pH enables the cellulose degradation by A. sinuosa at an early stage of the process. The results of this study may be useful for a more efficient industrial application of biomass by means of brown-rot fungi.

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Section: Introductionmentioning

confidence: 99%

Cellulolytic activity of brown-rot Antrodia sinuosa at the initial stage of cellulose degradation

et al. 2019

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“…Numerous lab experiments studying the animal health and metabolism or the methane production have been carried out using the rumen microbial microbiome. In such in vitro experiments, the ratio of rumen fluid/fermentation volume is quite high (0.25 up to 1) (Agematu et al 2017 ; Judd and Kohn 2018 ). However, if the rumen fluid is to be used for the hydrolysis of lignocellulosic substrates, not only the dry matter content of the rumen fluid, but also the SCFA content at those high ratios introduce complications and uncertainty on the efforts to calculate fermentation yields for the desired substrate.…”

Section: Discussionmentioning

confidence: 99%

A cellulolytic fungal biofilm enhances the consolidated bioconversion of cellulose to short chain fatty acids by the rumen microbiome

Xiros

Shahab

Studer

2019

Appl Microbiol Biotechnol

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The ability of the multispecies biofilm membrane reactors (MBM reactors) to provide distinguished niches for aerobic and anaerobic microbes at the same time was used for the investigation of the consolidated bioprocessing of cellulose to short chain fatty acids (SCFAs). A consortium based consolidated bioprocess (CBP) was designed. The rumen microbiome was used as the converting microbial consortium, co-cultivated with selected individual aerobic fungi which formed a biofilm on the tubular membrane flushed with oxygen. The beneficial effect of the fungal biofilm on the process yields and productivities was attributed to the enhanced cellulolytic activities compared with those achieved by the rumen microbiome alone. At 30 °C, the MBM system with Trichoderma reesei biofilm reached a concentration 39% higher (7.3 g/L SCFAs), than the rumen microbiome alone (5.1 g/L) using 15 g/L crystalline cellulose as the substrate. Fermentation temperature was crucial especially for the composition of the short chain fatty acids produced. The temperature increase resulted in shorter fatty acids produced. While a mixture of acetic, propionic, butyric, and caproic acids was produced at 30 °C with Trichoderma reesei biofilm, butyric and caproic acids were not detected during the fermentations at 37.5 °C carried out with Coprinopsis cinerea as the biofilm forming fungus. Apart from the presence of the fungal biofilm, no parameter studied had a significant impact on the total yield of organic acids produced, which reached 0.47 g of total SCFAs per g of cellulose (at 30 °C and at pH 6, with rumen inoculum to total volume ratio equal to 0.372). Electronic supplementary material The online version of this article (10.1007/s00253-019-09706-1) contains supplementary material, which is available to authorized users.

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“…The experimental conditions of RMS have been described in previous articles [5,6]. Briefly, the cultivation was carried out anaerobically by intermittent ventilation with nitrogen gas at an incubation temperature of 39°C and the contents in the reactor were agitated at 30-40 rpm using impellers.…”

Section: Continuous Cultivation Of Ruminal Bacteria Using Rmsmentioning

confidence: 99%

“…Acetic, propionic, and butyric acids in the effluent from the reactor were quantified by HPLC. The HPLC conditions and preparation of HPLC sample have been described in previous articles [5,6].…”

Section: High-performance Liquid Chromatography (Hplc) Analysismentioning

confidence: 99%

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Characterization of the Rumen-Mimetic Continuous Cultivation System for Volatile Fatty Acid Production from Lignocellulosic Biomass

Agematu¹,

Watanabe²,

Takahashi³

2021

IJMB

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The rumen-mimetic continuous cultivation system (RMS) was used to produce volatile fatty acids (VFAs), such as acetic, propionic, and butyric acids, from lignocellulosic biomass. Typical 12 species of ruminal bacteria were detected in the culture broth cultivated by RMS using species-specific PCR assay. These species are known to be cellulolytic, hemicellulolytic, proteolytic, amylolytic, and lipolytic bacteria and methanogens. Therefore, RMS was characterized to be ruminal fermentation like the digestive system of roughage in the rumen of cattle. Using RMS, the ruminal bacteria were continuously cultivated for 120 days to produce VFAs. The yield of total VFAs from 20-50 µm rice straw was 167% higher than that from 300-1000 µm rice straw. However, the productivity was not increased by pulverization of the substrate. The yield and productivity of acetic acid from 20-50 µm rice straw were 0.147 g/g and 34.8 mg/L/h, respectively, and those of propionic acid were 0.104 g/g and 24.6 mg/L/h, respectively. The selectivity (P/A ratio) of acetic and propionic acid production from microcrystalline cellulose at pH 6.5 and 7.0 were 0.83±0.07 and 0.31±0.03, respectively. The ruminal bacteria could not continue to produce VFAs at pH 6.0. The yield and productivity of acetic acid from microcrystalline cellulose at pH 6.5 were 0.234 g/g and 51.7 mg/L/h, respectively, and those of propionic acid were 0.223 g/g and 49.3 mg/L/h, respectively. This study proposes that in order to increase the productivity of RMS, it is necessary to increase the ruminal bacterial biomass by recycling biomass (flocs) using a settling tank.

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Continuous volatile fatty acid production from lignocellulosic biomass by a novel rumen-mimetic bioprocess

Cited by 27 publications

References 30 publications

Cellulolytic activity of brown-rot Antrodia sinuosa at the initial stage of cellulose degradation

Cellulolytic activity of brown-rot Antrodia sinuosa at the initial stage of cellulose degradation

A cellulolytic fungal biofilm enhances the consolidated bioconversion of cellulose to short chain fatty acids by the rumen microbiome

Characterization of the Rumen-Mimetic Continuous Cultivation System for Volatile Fatty Acid Production from Lignocellulosic Biomass

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