Engineering Bacterial Sugar Catabolism and Tolerance Toward Lignocellulose Conversion

AbstractThe pretreatment of lignocellulosic material performed to improve substrate’s susceptibility to enzymatic hydrolysis is usually accompanied by reactions leading to the synthesis of compounds that inhibit the metabolic activity of microorganisms. Their toxicity is the main obstacle to the successful bioconversion of lignocellulosic hydrolysates. The identification of these inhibitors and the choice of the optimal detoxication method are crucial for the improving the efficiency of fermentation processes. Material rinsing with water after processing is a common detoxication practice. However, it generates material losses, thus affecting contents of saccharides in the fermentation medium, which may in turn trigger higher costs of lignocellulose conversion to ethanol and other products with a higher added value. A study was undertaken to determine the effect of selected methods for the detoxication of an enzymatic hydrolysate from Miscanthus giganteus on the fermentation efficiency of saccharide derivatives. The experiment conducted with Mucor rouxii DSM 1191 demonstrated the usability of the detoxication method based on the activated carbon. After 96-h fermentation of Miscanthus hydrolysates, the alcohol content in the post-reaction medium was higher by 14% than in the control experiment wherein the material was rinsed with water after pretreatment. The experiment carried out with Saccharomyces cerevisiae 7, NRRL 978 showed no positive impact of the alternative detoxication methods replacing material rinsing on the efficiency of ethanol synthesis. The highest concentration of this metabolite (2.04% (v/v)) was obtained in the experimental variant in which the mentioned operation was coupled with detoxication of hydrolysates using calcium hydroxide.

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Complete lignocellulose conversion with integrated catalyst recycling yielding valuable aromatics and fuels

Nature Catalysis ◽

10.1038/s41929-017-0007-z ◽

2018 ◽

Vol 1 (1) ◽

pp. 82-92 ◽

Cited By ~ 141

Author(s):

Zhuohua Sun ◽

Giovanni Bottari ◽

Anastasiia Afanasenko ◽

Marc C. A. Stuart ◽

Peter J. Deuss ◽

...

Keyword(s):

Catalyst Recycling ◽

Lignocellulose Conversion

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Isolation and Screening of Microorganisms for the Effective Pretreatment of Lignocellulosic Agricultural Wastes

BioMed Research International ◽

10.1155/2021/5514745 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Zichen Zhang ◽

Aabid Manzoor Shah ◽

Hassan Mohamed ◽

Nino Tsiklauri ◽

Yuanda Song

Keyword(s):

Enzyme Activities ◽

Dominant Role ◽

Value Added ◽

Ligninolytic Enzymes ◽

Agricultural Wastes ◽

Submerged Cultivation ◽

X Ray Diffraction ◽

Lignocellulose Conversion ◽

Selective Delignification ◽

Hydrolysis Of Cellulose

Lignocellulosic waste is the most abundant biorenewable biomass on earth, and its hydrolysis releases highly valued reducing sugars. However, the presence of lignin in the biopolymeric structure makes it highly resistant to solubilization thereby hindering the hydrolysis of cellulose and hemicellulose. Microorganisms are known for their potential complex enzymes that play a dominant role in lignocellulose conversion. Therefore, the current study was designed to isolate and screen potential microorganisms for their selective delignification ability for the pretreatment of lignocellulosic biomass. An extensive isolation and screening procedure yielded 36 desired isolates (22 bacteria, 7 basidiomycete fungi, and 7 filamentous fungi). Submerged cultivation of these desired microorganisms revealed 4 bacteria and 10 fungi with potent lignocellulolytic enzyme activities. The potent isolates were identified as Pleurotus, Trichoderma, Talaromyces, Bacillus, and Chryseobacterium spp. confirmed by morphological and molecular identification. The efficiency of these strains was determined through enzyme activities, and the degraded substrates were analyzed through scanning electron microscopy (SEM) and X-ray diffraction (XRD). Among all isolated microbes, Pleurotus spp. were found to have high laccase activity. The cellulose-decomposing and selective delignification strains were subjected to solid-state fermentation (SSF). SSF of field waste corn stalks as a single-carbon source provides Pleurotus spp. better condition for the secretion of ligninolytic enzymes. These isolated ligninolytic enzymes producing microorganisms may be used for the effective pretreatment of lignocellulosic agricultural wastes for the production of high value-added natural products by fermentation.

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Bioreactors for lignocellulose conversion into fermentable sugars for production of high added value products

Applied Microbiology and Biotechnology ◽

10.1007/s00253-015-7125-9 ◽

2015 ◽

Vol 100 (2) ◽

pp. 597-611 ◽

Cited By ~ 37

Author(s):

Rossana Liguori ◽

Valeria Ventorino ◽

Olimpia Pepe ◽

Vincenza Faraco

Keyword(s):

Added Value ◽

Fermentable Sugars ◽

Lignocellulose Conversion

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Enhanced Biomass Yield of and Saccharification in Transgenic Tobacco Over-Expressing β-Glucosidase

Biomolecules ◽

10.3390/biom10050806 ◽

2020 ◽

Vol 10 (5) ◽

pp. 806

Author(s):

Eun Jin Cho ◽

Quynh Anh Nguyen ◽

Yoon Gyo Lee ◽

Younho Song ◽

Bok Jae Park ◽

...

Keyword(s):

Transgenic Tobacco ◽

Biomass Yield ◽

Thermotoga Maritima ◽

Total Biomass ◽

Transgenic Tobacco Plants ◽

Wild Type ◽

Tobacco Plants ◽

Lignocellulose Conversion ◽

Nicotiana Tabacum L ◽

Genome Transcription

Here, we report an increase in biomass yield and saccharification in transgenic tobacco plants (Nicotiana tabacum L.) overexpressing thermostable β-glucosidase from Thermotoga maritima, BglB, targeted to the chloroplasts and vacuoles. The transgenic tobacco plants showed phenotypic characteristics that were significantly different from those of the wild-type plants. The biomass yield and life cycle (from germination to flowering and harvest) of the transgenic tobacco plants overexpressing BglB were 52% higher and 36% shorter than those of the wild-type tobacco plants, respectively, indicating a change in the genome transcription levels in the transgenic tobacco plants. Saccharification in biomass samples from the transgenic tobacco plants was 92% higher than that in biomass samples from the wild-type tobacco plants. The transgenic tobacco plants required a total investment (US$/year) corresponding to 52.9% of that required for the wild-type tobacco plants, but the total biomass yield (kg/year) of the transgenic tobacco plants was 43% higher than that of the wild-type tobacco plants. This approach could be applied to other plants to increase biomass yields and overproduce β-glucosidase for lignocellulose conversion.

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Convergent production of 2,5-furandicarboxylic acid from biomass and CO2

Green Chemistry ◽

10.1039/c9gc00869a ◽

2019 ◽

Vol 21 (11) ◽

pp. 2923-2927 ◽

Cited By ~ 10

Author(s):

Hua Zhou ◽

Huanghui Xu ◽

Xueke Wang ◽

Yun Liu

Keyword(s):

Lignocellulose Conversion ◽

Furandicarboxylic Acid

We report a rationally designed process for complete lignocellulose conversion and CO2 utilization to convergently produce 2,5-furandicarboxylic acid (FDCA) that can be used in bioplastics and resins.

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