Project description:Ahmad2017 - Genome-scale metabolic model
(iGT736) of Geobacillus thermoglucosidasius (C56-YS93)
This model is described in the article:
A Genome Scale Model of
Geobacillus thermoglucosidasius (C56-YS93) reveals its
biotechnological potential on rice straw hydrolysate
Ahmad Ahmada, Hassan B. Hartmanb, S.
Krishnakumara, David A. Fellb, Mark G. Poolmanb, Shireesh
Srivastavaa
Journal of Biotechnology
Abstract:
Rice straw is a major crop residue which is burnt in many
countries, creating significant air pollution. Thus,
alternative routes for disposal of rice straw are needed.
Biotechnological treatment of rice straw hydrolysate has
potential to convert this agriculture waste into valuable
biofuel(s) and platform chemicals. Geobacillus
thermoglucosidasius is a thermophile with properties specially
suited for use as a biocatalyst in lignocellulosic
bioprocesses, such as high optimal temperature and tolerance to
high levels of ethanol. However, the capabilities of
Geobacillus thermoglucosidasius to utilize sugars in rice straw
hydrolysate for making bioethanol and other platform chemicals
have not been fully explored. In this work, we have created a
genome scale metabolic model (denoted iGT736) of the organism
containing 736 gene products, 1159 reactions and 1163
metabolites. The model was validated both by purely theoretical
approaches and by comparing the behaviour of the model to
previously published experimental results. The model was then
used to determine the yields of a variety of platform chemicals
from glucose and xylose — two primary sugars in rice
straw hydrolysate. A comparison with results from a model of
Escherichia coli shows that Geobacillus thermoglucosidasius is
capable of producing a wider range of products, and that for
the products also produced by Escherichia coli, the yields are
comparable. We also discuss strategies to utilise arabinose, a
minor component of rice straw hydrolysate, and propose
additional reactions to lead to the synthesis of xylitol, not
currently produced by Geobacillus thermoglucosidasius. Our
results provide additional motivation for the current
exploration of the industrial potential of Geobacillus
thermoglucosidasius and we make our model publicly available to
aid the development of metabolic engineering strategies for
this organism.
This model is hosted on
BioModels Database
and identified by:
MODEL1703060000.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
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the public domain worldwide. Please refer to
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Project description:Here comparative transcriptomic analyses of Penicillium oxalicum grown on wheat bran (WB), WB plus rice straw (WR) and WB plus Avicel (WA) as the sole carbon source under solid-state fermentation (SSF) revealed that most of differentially expressed genes (DEGs) were involved in metabolism specifically carbohydrate metabolism.
Project description:To reach an economically feasible bioethanol process from lignocellulose, efficient fermentation by yeast of all sugars present in the hydrolysate has to be achieved. However, when exposed to lignocellulosic hydrolysate, Saccharomyces cerevisiae is challenged with a variety of inhibitors that reduce yeast viability, growth and fermentation rate, and in addition damage cellular structures. In order to evaluate the yeast capability to adapt to lignocellulosic hydrolysates and to investigate the yeast molecular response to inhibitors, fed-batch cultivation of an industrial S. cerevisiae strain was performed using either spruce hydrolysate or a sugar medium as feed. The physiological effects of cultivating yeast in spruce hydrolysate was comprehensively studied by assessment of yeast performance in simultaneous saccharification and fermentation (SSF), measurement of furaldehyde reduction activity, assessment of conversion of phenolic compounds and genome wide transcription analysis. The yeast cultivated in spruce hydrolysate developed a rapid adaptive response to lignocellulosic hydrolysate, which significantly improved its fermentation performance in subsequent SSF experiments. Yeast adaptation to hydrolysate was shown to involve induction of NADPH-dependent aldehyde reduction activity and conversion of phenolic compounds during the fed-batch cultivation and these properties were correlated to the expression of several genes encoding oxido-reductase activities, notably AAD4, ADH6, OYE2/3 and YML131w. The other most significant transcriptional changes involved genes involved in transport mechanisms, such as YHK8, FLR1 or ATR1. A large set of genes were found to be associated to transcription factors involved in stress response (Msn2p, Msn4p, Yap1p but also cell growth and division (Gcr4p, Ste12p, Sok2p) that were most likely activated at the post-transcriptional level.
Project description:Straw return is crucial for the sustainable development of rice planting. To investigate the response of rice leaves to rice straw return, we analyzed the physiological index of rice leaves and measured differentially expressed protein (DEPs) and differentially expressed metabolites (DEMs) levels in rice leaves by the use of proteomics and metabolomics approaches. The results showed that, compared with no rice straw return, rice straw return significantly decreased the dry weight of rice plants and nonstructural carbohydrate contents and destroyed the chloroplast ultrastructure. In rice leaves under rice straw return, 329 DEPs were upregulated, 303 DEPs were downregulated, 44 DEMs were upregulated, and 71 DEMs were downregulated. These DEPs and DEMs were mainly involved in various molecular processes, including photosynthesis, carbon fixation in photosynthetic organisms, glycolysis, and the citric acid cycle. Rice straw return promoted the accumulation of osmotic adjustment substances, such as organic acids, amino acids, and other substances, and reduced the material supply and energy production of carbon metabolism, thus inhibiting the growth of rice.
Project description:Various saprotrophic microorganisms, especially filamentous fungi, can efficiently degrade lignocellulose that is one of the most abundant natural material on earth. It consists of complex carbohydrates and aromatic polymers found in plant cell wall and thus in plant debris. Aspergillus fumigatus Z5 was isolated from compost heaps and showed highly efficient plant biomass-degradation capability.Genome analysis revealed an impressive array of genes encoding cellulases, hemicellulases, and pectinases involved in lignocellulosic biomass degradation. We sequenced the transcriptomes of Aspergillus fumigatus Z5 induced by sucrose, xylan, cellulose and rice straw, respectively. There were 444, 1711 and 1386 significantly differently (q-value ⤠0.0001 and |log2 of the ratio of the RPM values| ⥠2) expressed genes in xylan, cellulose and rice straw,respectively, relative to sucrose control. After incubation at 45 â, 145rpm for 20 hours with sucrose as the carbon source, mycelia were induced for 16 hours using xylan, cellulose and rice straw, respectively. Transcriptome induced by sucrose was used as the control when comparing the differences between other three transcriptomes (induced by xylan, cellulose and rice straw, respectively).
Project description:Total RNA from rumen epithelial tissues of cows fed alfalfa hay (AL),Rice straw (RS) or Corn stover (CS)diet were sequenced using Illumina Hiseq 2000 system. For comparative analysis, differentially expressed genes were identified with edgeR.
Project description:The physiology of ethanologenic Escherichia coli grown anaerobically in alkaline-pretreated plant hydrolysates is not well studied. To gain insight into how E. coli responds to such hydrolysates, we studied an E. coli K-12 ethanologen fermenting a hydrolysate prepared from corn stover pre-treated by ammonia fiber expansion. Despite the high sugar content (~6% glucose, 3% xylose) and relatively low toxicity of this hydrolysate, E. coli ceased growth long before glucose was depleted. Nevertheless, the cells remained metabolically active and continued conversion of glucose to ethanol until all glucose was consumed. Gene expression profiling revealed complex and changing patterns of metabolic physiology and cellular stress responses throughout the different stages of growth. During the exponential and transition phases of growth, high cell maintenance and stress response costs were mitigated, in part, by free amino acids available in the hydrolysate media. However, after the majority of amino acids were depleted from the media cells entered stationary phase and ATP derived from glucose fermentation was consumed entirely by the demands of cell maintenance in the hydrolysate. Comparative gene expression profiling and metabolic modeling of the ethanologen suggested that the high energetic cost of mitigating osmotic, lignotoxin and ethanol stress collectively limits growth, sugar utilization rates and ethanol yields in alkaline-pretreated lignocellulosic hydrolysates. 38 samples in total. 24 samples were derived from biological replicate fermentations of alkaline-pretreated cornstover hydrolysate (12 datapoint time-series per fermentation). The remaining samples were obtained from fermentations conducted in defined media (Glucose Minimal Media (GMM, n=7), Synthetic Hydrolysate media (SynH, n=7)).
Project description:Total RNA from duodenum, jejunum, liver and mammary gland tissues of cows fed alfalfa hay (AL),Rice straw (RS) or Corn stover (CS) diet were sequenced using Illumina HiSeq 2000 system. For comparative analysis, differentially expressed genes were identified with edgeR and SAS software.
Project description:Parascedosporium putredinis NO1 was grown for 4 days on six lignocellulosic substrates: Kraft Lignin (LI), Sugar Cane Bagasse (SC), Rice Straw (RS), Wheat Straw (WS), Wheat Bran (WB), and Empty Fruit Bunches from Palm Oil (EF). Proteins were harvested from the culture supernatant and from the insoluble fraction using a biotin-labelling approach to target the proteins bound to the lignocellulosic substrates.