Unravelling the Interactions between Hydrolytic and Oxidative Enzymes in Degradation of Lignocellulosic Biomass by<i>Sporothrix carnis</i>under Various Fermentation Conditions

Ogunyewo, Olusola A.; Olajuyigbe, Folasade M.

doi:10.1155/2016/1614370

Cited by 12 publications

(6 citation statements)

References 34 publications

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“…Dual hydrolytic and oxidative enzyme systems have the potential to boost effectiveness for deconstructing lignocellulosic biomass (Woolridge 2014;Ogunyewo and Olajuyigbe 2016;Bohacz 2017;Bomble et al 2017). However, the hydrolytic enzyme xylanase is susceptible to inactivation via oxidation, particularly by the LMS.…”

Section: Discussionmentioning

confidence: 99%

Establishing the oxidative tolerance of Thermomyces lanuginosus xylanase

Badon

Tekverk

Vishnosky

et al. 2019

J of Applied Microbiology

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Aims This work aims to determine the tolerance of xylanase towards enzyme‐generated oxidative conditions, such as those produced by the peroxidase or laccase mediator systems (LMS). Methods and Results The activity of Thermomyces lanuginosus xylanase was measured after incubation with lignin peroxidase, manganese peroxidase or laccase plus various mediators. The laccase system, using mediators such as 1‐hydroxybenzotriazole and violuric acid, resulted in complete loss of xylanase activity, accompanied by an increase in the solution potential. However, an increase in solution potential alone was not sufficient to inactivate xylanase, nor was loss of xylanase activity always accompanied by a significant increase in solution potential, as observed with N‐hydroxyphthalimide as the mediator. Neither lignin peroxidase nor manganese peroxidase impacted xylanase activity; only extended treatment with elevated hydrogen peroxide concentration promoted modest xylanase activity loss. The mechanism of inactivation as determined by the tryptophan‐modifying reagent N‐bromosuccinimide (NBS) indicated that oxidation of just one of the eight tryptophan residues of T. lanuginosus xylanase would be sufficient to result in complete loss of xylanase activity, since xylanase is completely inactivated at 1 : 1 molar ratio of NBS to xylanase. Conclusions While showing tolerance to peroxidase‐based enzyme systems, T. lanuginosus xylanase is readily inactivated in the presence of the LMS. Based upon treatment with NBS as the oxidant, inactivation can be attributed to modification of a single tryptophan residue. Significance and Impact of the Study The simultaneous application of mixed hydrolytic and oxidative enzyme systems is of importance to biomass processing industries. Understanding the tolerance of xylanase to oxidative conditions will facilitate the design of reaction conditions or enzyme variants to maximize the impact of mixed enzyme systems.

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Section: Discussionmentioning

confidence: 99%

Establishing the oxidative tolerance of Thermomyces lanuginosus xylanase

Badon

Tekverk

Vishnosky

et al. 2019

J of Applied Microbiology

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“…The two-step process allows us to separate the supernatant and the pulp which are hydrolysed separately by the microbial cultures producing hydrolysing enzymes. Usually, the supernatant is either again added to the biomass or is fermented separately for the production of biofuels [27]. The present method allows us to utilise the crystalline cellulose present in the supernatant to produce simple sugars like glucose.…”

Section: Discussionmentioning

confidence: 99%

“…To our knowledge, this is the first study where the flow through or the supernatant of the acid-treated biomass is being hydrolysed by enzymes to produce simple sugars. It is hypothesised that the cellulase is utilising the amorphous cellulose present in the supernatant fraction whereas, the laccase is aiding in the biodegradation of any lignin present in the supernatant fraction serving the cellulase enzyme to utilise cellulose more efficiently [27,28]. The highest amount of sugar (glucose) obtained after the cellulase-laccase hydrolysis process of the acid pre-treated rice straw supernatant was 205 mg/g of rice straw.…”

Section: Discussionmentioning

confidence: 99%

A novel approach to produce glucose from the supernatant obtained upon the dilute acid pre-treatment of rice straw and synergistic action of hydrolytic enzymes producing microbes

2018

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The present work refers to a process involving the use of dilute nitric acid pretreatment and enzymatic hydrolysis for the transformation of rice straw into simple sugars. Acid pre-treated rice straw was separated into the pulp and supernatant through centrifugation and filtration. The two fractions are then converted into simple sugars by combined action of microbes producing cellulase and laccase enzymes. These microbes were isolated from soil samples which were collected from different locations with varying altitudes, expected to harbour microbes with high-hydrolysing activity. The nitric acid pretreatment was carried out at 30 °C, 200 rpm for 72 h. After 72 h, the culture supernatants were analysed for the presence of glucose with the help of HPLC. The supernatant fraction separated after the acid pre-treated rice straw produced highest amount of glucose (205 mg/g of rice straw) upon subsequent hydrolysis with synergistic action of cellulase and laccase-producing microbes.

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“…[76] Research efforts where enzyme synergy has been studied for this purpose are, for instance, the production of arabinoxylo-oligosaccharides from wheat bran xylan for food applications, [77] and the degradation of corncob biomass by synergistic interactions between hydrolytic and oxidative enzymes. [78] The practical knowledge of enzyme mixture optimization for other applications can also be of interest for pulp and paper bleaching approaches. In addition to optimizing enzyme mixtures, the application of newly designed enzymes might be promising as well.…”

Section: Lessons Learned From Biorefineries Implementing Enzymatic Hy...mentioning

confidence: 99%

Synergism of enzymes in chemical pulp bleaching from an industrial point of view: A critical review

Immerzeel

Fiskari

2022

Can J Chem Eng

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Enzymes are biological catalysts and are very specific, catalyzing either a single chemical reaction or a limited number of closely related reactions. For example, xylanases are enzymes that catalyze the cleavage of polymeric xylan and thereby break down this hemicellulose. The first xylanase enzyme preparations used in the bleaching process of chemical pulp also contained cellulase, which catalyzes the hydrolysis of cellulose. This obviously had an adverse effect on pulp yield and quality. Unfortunately, this setback gave enzyme-assisted pulp bleaching a negative reputation. At a later stage, enzyme producers managed to engineer enzyme production strains that generated cellulase-free xylanase preparations. However, due to the initial negative experiences with the earlier enzyme mixtures, only a limited number of companies in the pulp industry have seriously considered using these so-called second-generation enzymes in their bleach plants. It is apparent that these improved enzyme preparations would bring about significant benefits in terms of chemical cost savings and effluent quality. In addition to xylanaseaided bleaching, it is possible to improve the effectivity further by adding other enzymes, such as lipase and esterase, to create an enzyme cocktail. This may be particularly beneficial in the bleaching of hardwood pulp, such as white birch, which often encounters complex and troublesome problems with wood extractives. By adding different types of enzymes at more than one position in the fiberline, even further improvements are possible. The main objective of this review is to discuss the advantages of incorporating modern enzyme preparations in the bleaching of chemical pulp.

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Unravelling the Interactions between Hydrolytic and Oxidative Enzymes in Degradation of Lignocellulosic Biomass bySporothrix carnisunder Various Fermentation Conditions

Cited by 12 publications

References 34 publications

Establishing the oxidative tolerance of Thermomyces lanuginosus xylanase

Establishing the oxidative tolerance of Thermomyces lanuginosus xylanase

A novel approach to produce glucose from the supernatant obtained upon the dilute acid pre-treatment of rice straw and synergistic action of hydrolytic enzymes producing microbes

Synergism of enzymes in chemical pulp bleaching from an industrial point of view: A critical review

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