Direct Fungal Production of Ethanol from High-Solids Pulps by the Ethanol-fermenting White-rot Fungus Phlebia sp. MG-60

Kamei, Ichiro; Hirota, Yoshiyuki; Meguro, Sadatoshi

doi:10.15376/biores.9.3.5114-5124

Cited by 16 publications

(5 citation statements)

References 22 publications

(26 reference statements)

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“…As an example of this metabolic ability among wooddecaying fungi, white rot species of the taxonomic order Polyporales, genus Phlebia have shown great potential for ethanol fermentation from untreated lignocellulose [11,[14][15][16]. The phlebioid fungi are able to decompose both the wood carbohydrates and lignin moieties via secretion of a wide array of carbohydrate-active enzymes (CAZy [17] http://www.cazy.org/) and lignin-modifying oxidoreductases [4,18].…”

Section: Introductionmentioning

confidence: 99%

Hypoxia is regulating enzymatic wood decomposition and intracellular carbohydrate metabolism in filamentous white rot fungus

Mattila

Mäkinen

Lundell

2020

Biotechnol Biofuels

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Background: Fungal decomposition of wood is considered as a strictly aerobic process. However, recent findings on wood-decaying fungi to produce ethanol from various lignocelluloses under oxygen-depleted conditions lead us to question this. We designed gene expression study of the white rot fungus Phlebia radiata (isolate FBCC0043) by adopting comparative transcriptomics and functional genomics on solid lignocellulose substrates under varying cultivation atmospheric conditions. Results: Switch to fermentative conditions was a major regulator for intracellular metabolism and extracellular enzymatic degradation of wood polysaccharides. Changes in the expression profiles of CAZy (carbohydrate-active enzyme) encoding genes upon oxygen depletion, lead into an alternative wood decomposition strategy. Surprisingly, we noticed higher cellulolytic activity under fermentative conditions in comparison to aerobic cultivation. In addition, our results manifest how oxygen depletion affects over 200 genes of fungal primary metabolism including several transcription factors. We present new functions for acetate generating phosphoketolase pathway and its potential regulator, Adr1 transcription factor, in carbon catabolism under oxygen depletion. Conclusions: Physiologically resilient wood-decomposing Basidiomycota species P. radiata is capable of thriving under respirative and fermentative conditions utilizing only untreated lignocellulose as carbon source. Hypoxiaresponse mechanism in the fungus is, however, divergent from the regulation described for Ascomycota fermenting yeasts or animal-pathogenic species of Basidiomycota.

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Section: Introductionmentioning

confidence: 99%

Hypoxia is regulating enzymatic wood decomposition and intracellular carbohydrate metabolism in filamentous white rot fungus

Mattila

Mäkinen

Lundell

2020

Biotechnol Biofuels

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“…where: a = theoretical yield (g) of ethanol from 1.0 kg glucose [39]. b = yield of glucose (kg) from 1.0 kg starch [39].…”

Section: Concentration Of Ethanol and Glucosementioning

confidence: 99%

Consolidated Bioprocess for Bioethanol Production from Raw Flour of Brosimum alicastrum Seeds Using the Native Strain of Trametes hirsuta Bm-2

et al. 2019

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Consolidated bioprocessing (CBP), which integrates biological pretreatment, enzyme production, saccharification, and fermentation, is a promising operational strategy for cost-effective ethanol production from biomass. In this study, the use of a native strain of Trametes hirsuta (Bm-2) was evaluated for bioethanol production from Brosimum alicastrum in a CBP. The raw seed flour obtained from the ramon tree contained 61% of starch, indicating its potential as a raw material for bioethanol production. Quantitative assays revealed that the Bm-2 strain produced the amylase enzyme with activity of 193.85 U/mL. The Bm-2 strain showed high tolerance to ethanol stress and was capable of directly producing ethanol from raw flour at a concentration of 13 g/L, with a production yield of 123.4 mL/kg flour. This study demonstrates the potential of T. hirsuta Bm-2 for starch-based ethanol production in a consolidated bioprocess to be implemented in the biofuel industry. The residual biomass after fermentation showed an average protein content of 22.5%, suggesting that it could also be considered as a valuable biorefinery co-product for animal feeding.Microorganisms 2019, 7, 483 2 of 16 use bioethanol as their main source of fuel. Ethanol blends vary depending on the country, containing from as low as 5% (E5) to 100% bioethanol (E100) [4][5][6][7].The growing global demand for bioethanol requires the use of alternative sources of raw materials to complement sugar cane and cornstarch, which are the main raw materials used to produce it. Starch crops are widely used for bioethanol production because of their worldwide availability, easy conversion, and high ethanol yield. These raw materials include cereals (60%-80% starch), tubers and roots (60%-90%), legumes (25%-50%), and green and immature fruits (up to 70% starch) [2].Conventionally, ethanol production from starch consists of several stages. Starch is subjected to a gelatinization process followed by a liquefaction step where starch is converted to dextrins and smaller molecules by the action of bacterial thermostable amylases at high temperatures (95-105 • C) and pH values between 6 and 6.5. This step is followed by saccharification. The liquefied starch is cooled, pH is adjusted to 4-4.5, temperatures to 60-65 • C, and a fungal glucoamylase is added to hydrolyze the oligosaccharides to glucose. The liquefaction and saccharification stages represent about 40%-50% of the total energy used during starch-based ethanol production [8][9][10].Owing to this technical complexity and the economic implications of this approach, other biological alternatives have been investigated, such as simultaneous saccharification and fermentation (SSF) and consolidated bioprocessing (CBP). The latter is a promising strategy for effective ethanol production, since it employs only one type of microorganism that is capable of both producing the enzymes to hydrolyze the biomass and converting sugars into ethanol [11,12]. This strategy has the potential of lowering the cost and enhancing the efficie...

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“…End-product (ethanol, organic acids) concentrations were uniformly converted into moles of carbon (for details, see chapter 3.3). Theoretical maximum of ethanol production from glucose was calculated similarly as in a previous study (Kamei et al, 2014). Dry weight change after 24 days in cultures on core board was calculated by subtracting the dry weight of non-inoculated control (only core board and medium) from the dry weight of fungal-inoculated core board culture.…”

Section: Statistical Analyses and Calculationsmentioning

confidence: 99%

“…As an alternative, white rot Basidiomycota fungi are capable of enzymatic degradation of all the wood and lignocellulose biopolymers (Floudas et al, 2012;Kuuskeri et al, 2016;Lundell et al, 2014;Nagy et al, 2016). The fungi are capable of growing on plant biomasses directly transforming their lignocellulose substrates into fermentable sugars thus enabling so called consolidated bioprocessing (CBP) and single-step processes for ethanol production (Dionisi et al, 2015;Jouzani and Taherzadeh, 2015;Kamei et al, 2012Kamei et al, , 2014Sarkar et al, 2012). Biological pre-treatments and CBP have so far been of lower interest compared to chemical pre-treatment methods.…”

Section: Introductionmentioning

confidence: 99%

Single-step, single-organism bioethanol production and bioconversion of lignocellulose waste materials by phlebioid fungal species

Mattila

Kuuskeri

Lundell

2017

Bioresource Technology

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Ethanol production from non-pretreated lignocellulose was carried out in a consolidated bioprocess with wood-decay fungi of phlebioid Polyporales. Ethanol production was attempted on glucose, spruce wood sawdust and waste core board. Substantial quantities of ethanol were achieved, and isolate Phlebia radiata 0043 produced 5.9g/L of ethanol reaching the yield of 10.4% ethanol from core board lignocellulose substrate. Acidic initial culture conditions (pH 3) induced ethanol fermentation compared to the more neutral environment. Together with bioethanol, the fungi were able to produce organic acids such as oxalate and fumarate, thus broadening their capacity and applicability as efficient organisms to be utilized for bioconversion of various lignocelluloses. In conclusion, fungi of Phlebia grow on, convert and saccharify solid lignocellulose waste materials without pre-treatments resulting in accumulation of ethanol and organic acids. These findings will aid in applying fungal biotechnology for production of biofuels and biocompounds.

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Direct Fungal Production of Ethanol from High-Solids Pulps by the Ethanol-fermenting White-rot Fungus Phlebia sp. MG-60

Cited by 16 publications

References 22 publications

Hypoxia is regulating enzymatic wood decomposition and intracellular carbohydrate metabolism in filamentous white rot fungus

Hypoxia is regulating enzymatic wood decomposition and intracellular carbohydrate metabolism in filamentous white rot fungus

Consolidated Bioprocess for Bioethanol Production from Raw Flour of Brosimum alicastrum Seeds Using the Native Strain of Trametes hirsuta Bm-2

Single-step, single-organism bioethanol production and bioconversion of lignocellulose waste materials by phlebioid fungal species

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