TITLE:
Production and Partial Characterization of an Extracellular Phytase Produced by Muscodor sp. under Submerged Fermentation
AUTHORS:
Natálie Martins Alves, Luis Henrique Souza Guimarães, Roberta Hilsdorf Piccoli, Patrícia Gomes Cardoso
KEYWORDS:
Endophytic Fungus, Muscodor sp., Phosphorus, Phytase, Phytic Acid
JOURNAL NAME:
Advances in Microbiology,
Vol.6 No.1,
January
22,
2016
ABSTRACT: In most of the raw materials
of plant origin used in animal feed, a portion of the phosphorus is stored as phytic
acid or phytate. Phytate is the main storage form of phosphorus in vegetables but
is not readily assimilated into food at low concentrations of the enzyme phytase.
In addition to making phosphorous unavailable, phytate binds divalent cations such
as calcium, copper, magnesium, iron, manganese and zinc, preventing the absorption
of these nutrients in the gut of the animal. Phytase promotes the hydrolysis of
the phytate phosphorus-releasing molecule, thereby increasing its bioavailability
in feed. Phytase is distributed in plant and animal tissues and it is synthesized
by some species of bacteria and fungi. The addition of this enzyme in the diet of
animals is essential to promote greater uptake of phosphorus and also contributes
to a decrease in the levels of phosphorus excreted by animals, thus reducing the
pollution caused by excess phosphorus in the environment. This work aimed to select
a fungus that stands out in the production of phytase among 100 isolates from Brazilian
caves belonging to the genera Aspergillus, Penicillium and Cladosporium and 13 endophytic fungi of the aerial part of the coffee
plant. For selection, the fungi were cultured in medium containing phytic acid as
a sole source of phosphorus. After seven days at 25 °C, we evaluated growth
and enzyme production by the presence of the phytic acid halo degradation (Enzymatic
Index-EI) surrounding the colonies. Forty-seven species produced phytase, and the
fungi Penicillium minioluteum (CF279)
and Muscodor sp. (UBSX) showed higher
degradation halos, 2.41 and 4.46, respectively. Considering the Muscodor sp. as the main source of phytase,
high enzymatic levels were obtained when the fungus was grown under submerged fermentation
with initial pH of 5.0 using wheat bran as additional carbon source for 144 h, at
125 rpm and 30 °C. Additionally, the enzyme was stable
at pH 5.0 and 40 °C, and inhibited (14% - 88%) by all compounds
analyzed. Then, this is the first study that reports the production of phytase by
the endophytic fungus Muscodor sp.