Production and Partial Characterization of an Extracellular Phytase Produced by &amp;lt;i&amp;gt;Muscodor&amp;lt;/i&amp;gt; sp. under Submerged Fermentation

Roberta Hilsdorf Piccoli,Luis Henrique Souza Guimarães,Natálie Martins Alves,Patrícia Gomes Cardoso

doi:10.4236/aim.2016.61003

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.

Highlights

IntroductionPhytic acid or phytate (myo-inositol hexakisphosphate) is the major source of phosphorus in animal feed, but animals cannot readily assimilate the element in this form
Phytic acid or phytate is the major source of phosphorus in animal feed, but animals cannot readily assimilate the element in this form
Among the hundred fungi isolated from caatinga caves and twelve endophytic fungi qualitatively analyzed, 28% were able to hydrolyze the phytic acid in the medium producing a clear halo

Summary

Introduction

Phytic acid or phytate (myo-inositol hexakisphosphate) is the major source of phosphorus in animal feed, but animals cannot readily assimilate the element in this form. The anti-nutritional effects of phytate remain unaffected [3]. Excretion of indigestible phytate, resulting in a large amount of phosphorous in manure, leads to redistribution of phosphorous in the soil [4]. It may leach into waterways and cause eutrophication that generates water quality issues. To avoid phytate-related issues, there is a need to introduce methods for degradation of phytate. The physical and chemical methods are expensive and reduce the nutritional value of the feed as well. Enzymatic degradation of phytate is an important alternative [5]

Objectives

Methods

Results

Conclusion