Superficial growth of Aspergillus ellipticus on lignocellulosic materials

Abstract

Lignocellulosic materials used in the food industry as containers or packaging can suffer fungal biodeterioration. For thisreason, the aim of this study was to evaluate the superficial growth of Aspergillus ellipticus on lignocellulosic materialsof food containers and packaging. A strain of A. ellipticus was selected for its high productivity of lignocellulolyticenzymes. Fragments the diameter of a 110 mm Petri dish were cut from six types of lignocellulosic materials used assupports: coated cardboard, uncoated cardboard, corrugated cardboard, kraft paper, cupcake wrapper and Whatman 5 filterpaper (positive control). The thickness (μm) and initial pH were measured for each material by contacting 2 g of materialwith 100 mL of distilled water at 15 °C and 40 °C and 10 μL of a spore suspension (106 spores/mL) was inoculated andincubated at 32 °C and 87% relative humidity in a desiccator with saturated barium solution. For 21 days, the diameter ofthe colony (mm) was measured growing on lignocellulosic materials. The pH of the materials was between 7.2 and 7.4,considering them neutral materials. The growth of the fungal colony was between 2 mm and 38.6 mm, being higher onfilter paper, followed by kraft paper, corrugated cardboard, uncoated cardboard, coated cardboard and cupcake wrapper.It is concluded that fungal biodeterioration of lignocellulosic packaging material for food can occur in conditions similarto those of tropical climates.