Fungi have long been an important source of nutrition and medically significant compounds [1-3]. Within industrial processes, fungi are commonplace in the transformation of raw materials and wastes into useful products [4-8]. More recently, the processing of fungal biomass for the fabrication of novel materials has gained much excitement and attraction as a renewable and ethical source of leather [9], packaging material [10], structural elements for buildings [11] and, most of interest for this work, insulation materials [12-14]. These materials are consistent in using filamentous fungi to produce interwoven networks of mycelium to achieve consistent bio-composite material performances [15]. Fungal cultures, in general, have similar conditions necessary for healthy growth, consisting of the correct nutritional components, carbohydrates, proteins and micronutrients [2].

Lignocellulosic residues, in their unprocessed form contain complex polymeric elements combined into one system, consisting of long chains of cellulose wound together with shorter chains of hemicellulose all bound together with layers of lignin. Lignin consists of aromatic groups linked together with ester bonds and is typically digested by the direct oxidation of the aromatic groups prior to the cleavage of the bridging oxygen sites [30]. This requires specific enzymes or strongly alkali conditions. Once the lignin is removed, the cellulose and hemicellulose become accessible for further digestion, which involves specific enzymes to break the polymeric chains into shorter units. The shorter units of carbohydrate demonstrate increasing solubility and ease of transport into the organism's cells [31], where they are needed [32]. 

Pre-digestion therefore, offers the potential for the standardisation of a wider range of feedstock materials and the bio remediation of otherwise difficult to deal with residues. The processes reported within the literature can be categorised into mechanical digestion, chemical digestion, enzymatic digestion and thermal degradation [34]. In order to explore the enhancement of filamentous fungal growth, various chemical and enzymatic treatments were explored on residues from the paper pulping process. This included acidic processes, including citric and sulfuric acid as well as basic treatments with sodium hydroxide. Enzymatic pre-digestions, using laccase and α-amylase were also explored. These tests were used to probe pre-digestion for enhanced growth speed.