Screening of bacterial extracellular xylanase producers with potential for cellulose pulp biobleaching

Rodrigues, Isabela da Silva Vasconcelos; Silva, Carolina Goes Silva e; Silva, Rafael Salomão da; Dolabella, Silvio Santana; Fernandes, Marcelo Ferreira; Fernandes, Roberta Pereira Miranda

doi:10.4025/actascibiolsci.v41i1.42101

Cited by 7 publications

(2 citation statements)

References 31 publications

(31 reference statements)

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“…Plates were impregnated with Congo red reagent (1 g/l distilled water) and left for 1 to 2 minutes and then Congo red was washed with normal sodium chloride. The formation of a colorless halo around the microbial colony was investigated and the ratio of halo to colony diameter was also calculated in three replications [22].…”

Section: Isolation and Characterization Of Microorganisms With High L...mentioning

confidence: 99%

A bioprocess for rapid compost production from rice straw using C/N ratio improvers and indigenous microorganisms at the lab and pilot scales

Sharafi

Jouzani

Karimi

et al. 2023

Preprint

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Management of agricultural waste like rice straw is essential in reducing environmental pollution and also creating added value. For this purpose, microorganisms with high hydrolytic activities were isolated from a simulated composting process. The effects of different materials, including rice straw, chicken manure, urea, olive pomace, and two groups of microbial boosters were assayed at lab-scale and pilot-scale for 60 days. The lab-scale results showed that two treatments containing chicken manure and microbial cocktails (E and F) improved the composting process significantly better than others. They had maximum temperature (59°C), C/N reduction rate (76.7%), and macro/microelements contents. Treatment E showed maximum wheat growth indexes, including dry (1.1 g) and wet (4.7 g) weight of aerial parts, plant height (47 cm), leaf area index (18.9 cm2), and leaf specific area index (45 cm2/g) compared to the control. The pilot-scale results showed that E treatment could reduce C/N (73.48%) better than F (58.32%) and control (13.03%) and it also caused most of the temperature changes up to 69°C. Finally, considering the highest germination index (96%) and lack of phytotoxicity, and also the greatest impact on wheat growth indexes, treatment E was selected for industrial production of compost.

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Section: Isolation and Characterization Of Microorganisms With High L...mentioning

confidence: 99%

A bioprocess for rapid compost production from rice straw using C/N ratio improvers and indigenous microorganisms at the lab and pilot scales

Sharafi

Jouzani

Karimi

et al. 2023

Preprint

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“…Compatible with our study, out of 257 isolates obtained from soil samples, 112 isolates represented by 44 % of total bacterial isolates showed xylanase enzyme activity detected by agar plate method. Among 112 isolates, 19 isolates were selected based on highest clear zone formed around their growth [26]. Also, out of 6 isolates, one isolate designated as Bact-1 was xylanase producer detected by agar plate methods [27].…”

Section: Isolation and Identification Of The Most Xylanase Producer B...mentioning

confidence: 99%

Xylanase from thermotolerant Bacillus haynesii strain, synthesis, characterization, optimization using Box-Behnken Design, and biobleaching activity

Bakry

Salem

Atta

et al. 2022

Biomass Conv. Bioref.

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The economic value of xylanolytic enzymes is derived from their use in a variety of industrial processes, which necessitates a cost-effective manufacturing procedure. In the current study, forty bacterial isolates were isolated from water samples and investigate their efficacy to producing xylanase enzyme. The most potent bacterial isolate was identified by sequencing and amplifications of 16Sr RNA gene as Bacillus haynesii strain K6. The impacts of various culture conditions on the productivity of xylane were examined. Data showed that the highest xylanase production was achieved at pH 7, in presence of 3 g/L xylan, 5 g/L peptone, and incubated at 40 °C for 24 h. The Box-Behnken model was used to find the best parameters for the relevant variables, and the results revealed an increase in xylanase production with values of 35.02 U/mL. The maximum precipitation of xylanase from the optimized culture was attained by ammonium sulfate (60%) followed by purification using dialysis and sephadex G100 column chromatography. The purified xylanase had a 12-fold enrichment, with a specific activity of 84 U/mg and a molecular weight approximately 439 KDa determined by thin-layer chromatography (TLC)/mass spectrometry. The amino acid analysis of the purified xylanase enzyme revealed the presence of 15 amino acids, with the highest concentrations of 1940 and 1520 mg/L for proline and cysteine, respectively. Finally, the physical properties of wastepaper pulp were improved after treatment with xylanase enzyme. The whiteness and softness of xylanase-treated wastepaper were improved with percentages of 34.6% and 16.2%, respectively. Therefore, we recommend the use of xylanase enzyme in the bleaching process as it is a biologically synthetic material, safe, and suitable for industrial use, and it reduces the use of harmful chemicals.

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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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Screening of bacterial extracellular xylanase producers with potential for cellulose pulp biobleaching

Cited by 7 publications

References 31 publications

A bioprocess for rapid compost production from rice straw using C/N ratio improvers and indigenous microorganisms at the lab and pilot scales

A bioprocess for rapid compost production from rice straw using C/N ratio improvers and indigenous microorganisms at the lab and pilot scales

Xylanase from thermotolerant Bacillus haynesii strain, synthesis, characterization, optimization using Box-Behnken Design, and biobleaching activity

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

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