Olive Mill Waste Enhances α-Glucan Content in the Edible Mushroom Pleurotus eryngii.

Sharon Avni,Hilla Hayby,Itamar Yadid,Nirit Ezove,Michal Karpovsky,Hilla Hanani,Yitzhak Hadar,Ofer Danay,Ofer Gover,Betty Schwartz

doi:10.3390/ijms18071564

Abstract

Mushroom polysaccharides are edible polymers that have numerous reported biological functions; the most common effects are attributed to β-glucans. In recent years, it became apparent that the less abundant α-glucans also possess potent effects in various health conditions. Here we explore several Pleurotus species for their total, β and α-glucan content. Pleurotus eryngii was found to have the highest total glucan concentrations and the highest α-glucans proportion. We also found that the stalks (stipe) of the fruit body contained higher glucan content then the caps (pileus). Since mushrooms respond markedly to changes in environmental and growth conditions, we developed cultivation methods aiming to increase the levels of α and β-glucans. Using olive mill solid waste (OMSW) from three-phase olive mills in the cultivation substrate. We were able to enrich the levels mainly of α-glucans. Maximal total glucan concentrations were enhanced up to twice when the growth substrate contained 80% of OMSW compared to no OMSW. Taking together this study demonstrate that Pleurotus eryngii can serve as a potential rich source of glucans for nutritional and medicinal applications and that glucan content in mushroom fruiting bodies can be further enriched by applying OMSW into the cultivation substrate.

Highlights

Mushrooms have a long history of consumption as food, and have remarkable therapeutic properties which are mainly recognized in oriental countries [1,2]
We found in the abovementioned study [27] that the glucan extracted from fruiting bodies grown on straw (FBE) contained 85% glucose as compared to that extracted from ME contained only 64% glucose
In studies aimed at examining the biological activity of α and β-glucans in different cell lines, it is essential to use soluble glucans in order to be supplemented into the cells’ medium

Summary

Introduction

Mushrooms have a long history of consumption as food, and have remarkable therapeutic properties which are mainly recognized in oriental countries [1,2]. Glucans (C6H12O5)n are polysaccharides built of glucose monosaccharides linked by α, β, or mixed α-β glycosidic bonds. Pleurotus genus’s (Oyster) pleuran is one of the most important and effective sources of β-glucans [6]. This compound is built of molecules of glucose linked by (1→3)-β bonds. This backbone with a linear structure is linked with side-chains built of glucopyranose molecules. Every four molecules of glucose in the backbone are connected with 0 to 6 molecules of glucopyranose as side-chains [7]

Objectives

Methods

Results

Conclusion