The enzymatic hydrolysis of proteins has been successful in improving their functional and bioactive properties. Extensive work has been conducted in applying plant, fungal, and bacterial proteases to animal protein sources (Ryder et al., 2015; Ha et al., 2012). Less work has been conducted examining the effects of fungal and bacterial proteases on plant proteins. This study characterised a range of bacterial and fungal proteases and evaluated the effects of selected bacterial and fungal proteases on a plant protein substrate assay. Commercially available proprietary fungal (FPII, F31K, and F60K), bacterial (HT, 4000 P, BS Conc), and plant (papain) proteases were screened for activity using the BODIPY-FL-Casein substrate. The soluble protein concentration of the protease powders was also assessed using the Bradford method. Based on the results of the screening, one fungal protease (F31K) and one bacterial protease (HT) were selected for further experiments. The selected proteases were then used to hydrolyse brown rice protein powder. The hydrolysis was conducted for up to 120 min at optimal conditions for each respective protease (pH 8.5 at 45 ⁰C, and pH 6 at 65 °C for F31K and HT, respectively). The resulting hydrolsates were evaluated for their soluble protein content using the Bradford method. The breakdown of protein was also visualised using SDS-PAGE. The mean enzyme activities ranged from 3.55×104 to 39.5×104 Δfluo.min-1.mg soluble protein-1 (for FPII and 4000 P, respectively). Both HT and F31K significantly increased (p < 0.05) the soluble protein concentration of the brown rice protein powder (from 0.586 to 2.21 and 3.12 mg/mL for HT and F31K, respectively). SDS-PAGE showed substantially different hydrolysis patterns for each protease over time. This study provides insights into how proteases from non-gut origin may overcome some of the challenges currently faced in the production of alternative proteins
