Improvement of Strain Penicillium sp. EZ-ZH190 for Tannase Production by Induced Mutation

Zakipour-Molkabadi, E.; Hamidi‐Esfahani, Zohreh; Sahari, Mohammad Ali; Azizi, Mohammad Hossein

doi:10.1007/s12010-013-0436-3

Cited by 5 publications

(5 citation statements)

References 32 publications

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“…The disadvantage of this treatment is the release of fermentation inhibitors such as the sugar degradation product furfural [3,4]. Depending on the fermentative microorganism, the release of these inhibitors can affect an organism’s ability to produce ethanol and even to grow [3,4]. A further consideration in choosing an organism for biofuel production is tolerance to fermentation end products such as ethanol.…”

Section: Introductionmentioning

confidence: 99%

Clostridium thermocellum transcriptomic profiles after exposure to furfural or heat stress

Wilson

Yang

Rodríguez

et al. 2013

Biotechnol Biofuels

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BackgroundThe thermophilic anaerobe Clostridium thermocellum is a candidate consolidated bioprocessing (CBP) biocatalyst for cellulosic ethanol production. It is capable of both cellulose solubilization and its fermentation to produce lignocellulosic ethanol. Intolerance to stresses routinely encountered during industrial fermentations may hinder the commercial development of this organism. A previous C. thermocellum ethanol stress study showed that the largest transcriptomic response was in genes and proteins related to nitrogen uptake and metabolism.ResultsIn this study, C. thermocellum was grown to mid-exponential phase and treated with furfural or heat to a final concentration of 3 g.L-1 or 68°C respectively to investigate general and specific physiological and regulatory stress responses. Samples were taken at 10, 30, 60 and 120 min post-shock, and from untreated control fermentations, for transcriptomic analyses and fermentation product determinations and compared to a published dataset from an ethanol stress study. Urea uptake genes were induced following furfural stress, but not to the same extent as ethanol stress and transcription from these genes was largely unaffected by heat stress. The largest transcriptomic response to furfural stress was genes for sulfate transporter subunits and enzymes in the sulfate assimilatory pathway, although these genes were also affected late in the heat and ethanol stress responses. Lactate production was higher in furfural treated culture, although the lactate dehydrogenase gene was not differentially expressed under this condition. Other redox related genes such as a copy of the rex gene, a bifunctional acetaldehyde-CoA/alcohol dehydrogenase and adjacent genes did show lower expression after furfural stress compared to the control, heat and ethanol fermentation profiles. Heat stress induced expression from chaperone related genes and overlap was observed with the responses to the other stresses. This study suggests the involvement of C. thermocellum genes with functions in oxidative stress protection, electron transfer, detoxification, sulfur and nitrogen acquisition, and DNA repair mechanisms in its stress responses and the use of different regulatory networks to coordinate and control adaptation.ConclusionsThis study has identified C. thermocellum gene regulatory motifs and aspects of physiology and gene regulation for further study. The nexus between future systems biology studies and recently developed genetic tools for C. thermocellum offers the potential for more rapid strain development and for broader insights into this organism’s physiology and regulation.

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Section: Introductionmentioning

confidence: 99%

Clostridium thermocellum transcriptomic profiles after exposure to furfural or heat stress

Wilson

Yang

Rodríguez

et al. 2013

Biotechnol Biofuels

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“…As a result, the improvement in enzymatic digestibility after AHP pretreatment is limited [16,17], and this lack of efficacy on woody biomass is a ubiquitous challenge faced by many pretreatment methods [5,18,19]. Although a few methods including organosolv, dilute acid, and SPORL (a sulfite pretreatment combined with mechanical size reduction) have been reported to be effective pretreatments for hybrid poplar [20,21], all of these methods still have drawbacks such as a high consumption of chemicals and the generation of fermentation inhibitors [22].…”

Section: Introductionmentioning

confidence: 99%

Rapid and effective oxidative pretreatment of woody biomass at mild reaction conditions and low oxidant loadings

Chen

Hegg

et al. 2013

Biotechnol Biofuels

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BackgroundOne route for producing cellulosic biofuels is by the fermentation of lignocellulose-derived sugars generated from a pretreatment that can be effectively coupled with an enzymatic hydrolysis of the plant cell wall. While woody biomass exhibits a number of positive agronomic and logistical attributes, these feedstocks are significantly more recalcitrant to chemical pretreatments than herbaceous feedstocks, requiring higher chemical and energy inputs to achieve high sugar yields from enzymatic hydrolysis. We previously discovered that alkaline hydrogen peroxide (AHP) pretreatment catalyzed by copper(II) 2,2΄-bipyridine complexes significantly improves subsequent enzymatic glucose and xylose release from hybrid poplar heartwood and sapwood relative to uncatalyzed AHP pretreatment at modest reaction conditions (room temperature and atmospheric pressure). In the present work, the reaction conditions for this catalyzed AHP pretreatment were investigated in more detail with the aim of better characterizing the relationship between pretreatment conditions and subsequent enzymatic sugar release.ResultsWe found that for a wide range of pretreatment conditions, the catalyzed pretreatment resulted in significantly higher glucose and xylose enzymatic hydrolysis yields (as high as 80% for both glucose and xylose) relative to uncatalyzed pretreatment (up to 40% for glucose and 50% for xylose). We identified that the extent of improvement in glucan and xylan yield using this catalyzed pretreatment approach was a function of pretreatment conditions that included H2O2 loading on biomass, catalyst concentration, solids concentration, and pretreatment duration. Based on these results, several important improvements in pretreatment and hydrolysis conditions were identified that may have a positive economic impact for a process employing a catalyzed oxidative pretreatment. These improvements include identifying that: (1) substantially lower H2O2 loadings can be used that may result in up to a 50-65% decrease in H2O2 application (from 100 mg H2O2/g biomass to 35–50 mg/g) with only minor losses in glucose and xylose yield, (2) a 60% decrease in the catalyst concentration from 5.0 mM to 2.0 mM (corresponding to a catalyst loading of 25 μmol/g biomass to 10 μmol/g biomass) can be achieved without a subsequent loss in glucose yield, (3) an order of magnitude improvement in the time required for pretreatment (minutes versus hours or days) can be realized using the catalyzed pretreatment approach, and (4) enzyme dosage can be reduced to less than 30 mg protein/g glucan and potentially further with only minor losses in glucose and xylose yields. In addition, we established that the reaction rate is improved in both catalyzed and uncatalyzed AHP pretreatment by increased solids concentrations.ConclusionsThis work explored the relationship between reaction conditions impacting a catalyzed oxidative pretreatment of woody biomass and identified that significant decreases in the H2O2, catalyst, and enzyme loading on the biomass as well a...

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“…In addition, this Penicillium ‐derived promoter Ppel may have broader applications in engineering other Penicillium species, which produced important industrial enzymes, such as pectinase in P. griseoroseum , cellulase in P. decumbens , and tannase in Penicillium sp. .…”

Section: Resultsmentioning

confidence: 99%

Characterization of the 5′ flanking region of lipase gene from Penicillium expansum and its application in molecular breeding

Zhang

Peng

et al. 2014

Biotech and App Biochem

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A major challenge for further promotion of lipase productivity in Penicillium expansum PE-12 is to find a suitable promoter that can function efficiently in this industrial strain. In this study, the 5' flanking region of P. expansum lipase (Ppel) containing a putative novel promoter sequence was characterized by fusing to β-glucuronidase (GUS) and subsequently introducing into P. expansum. As a result, all the transformants showed blue color quickly after incubation in GUS detection buffer, suggesting a strong promoter activity of this fragment. Glucose repression was identified for the promoter, whereas olive oil acted as a positive regulator. Facilitated by this novel promoter, P. expansum PE-12 was genetically modified, with an improved lipase yield, via a recombinant plasmid with P. expansum lipase gene (PEL) under the control of Ppel promoter and TtrpC terminator. The highest lipase yield among the modified strains could attain 2,100 U/mL, which is more than twofold of the previous industrial strain (900 U/mL). The engineered strain through molecular breeding method as well as this new promoter has great value in lipase industry.

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Improvement of Strain Penicillium sp. EZ-ZH190 for Tannase Production by Induced Mutation

Cited by 5 publications

References 32 publications

Clostridium thermocellum transcriptomic profiles after exposure to furfural or heat stress

Clostridium thermocellum transcriptomic profiles after exposure to furfural or heat stress

Rapid and effective oxidative pretreatment of woody biomass at mild reaction conditions and low oxidant loadings

Characterization of the 5′ flanking region of lipase gene from Penicillium expansum and its application in molecular breeding

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