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Extracellular expression of a thermostable phytase (phyA) in Kluyveromyces lactis

Paper ID Volume ID Publish Year Pages File Format Full-Text
34652 45038 2014 8 PDF Available
Title
Extracellular expression of a thermostable phytase (phyA) in Kluyveromyces lactis
Abstract

•Phytase from A. niger NII 08121 was expressed in Kluyveromyces lactis in secretory form.•Purified protein was heavily glycosylated.•Recombinant enzyme was thermostable at 100 °C for 1 h.•Role of asparagine 345 in thermostability was enlightened.

Functional expression of a thermostable phytase from A. niger was achieved in Kluyveromyces lactis GG799 cells. Effective secretion of recombinant enzyme (198 U ml−1) in the fermentation broth at 72 h incubation at 22 °C was obtained. Purified enzyme showed a specific activity of 72 U mg−1) and was detected on SDS-PAGE as a heavily glycosylated protein with a molecular weight of ≥140 kDa. Optimum temperature of the enzyme was at 55 °C and it showed a characteristic bi-hump pH profile with two pH optima (at pH 2.5 and 5.5). Enzyme showed considerable pepsin resistance with 60% activity retention after incubation with pepsin at the ratio of 1:1000. Enzyme was thermostable retaining 69 and 37% activity at 90 and 100 °C for 10 min respectively and remained active at these temperatures till 1 h. Deglycosylation studies demonstrated negligible effect of N-linked glycans on thermal properties. Multiple sequence alignment data revealed a conserved Asn at position 345 of this phytase which might contribute to its thermal properties. This thermostable phytase coupled with its noticeable protease resistance could be a better alternative to current commercial phytases.

Keywords
A. niger; Phytase; K. lactis; Thermostability; Pepsin; Deglycosylation
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Extracellular expression of a thermostable phytase (phyA) in Kluyveromyces lactis
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 49, Issue 9, September 2014, Pages 1440–1447
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us