Improving the extraction conditions of endoglucanase produced by Aspergillus niger under solid-state fermentation

Abstract

-Production of cellulases under solid-state fermentation (SSF) is a promising technique that can help to reduce costs. Besides optimizing the production process, it is also important to consider enzyme recovery during the extraction step. Here, an experimental design methodology was used to investigate the effects of the operational parameters solid to liquid ratio (1:3, 1:6 and 1:9), stirring rate (80, 120 and 160 rpm), and temperature (10, 22 and 35 °C) on the recovery of endoglucanases produced by Aspergillus niger cultivated under SSF. Statistical analysis revealed that only the solid to liquid ratio had a significant influence on endoglucanase extraction. The highest endoglucanase recovery (35.7 U/g) was achieved using 0.2 mol/L acetate buffer at pH 4.8, together with a solid to liquid ratio of 1:9 and an agitation time of 10 minutes. In sequential extraction experiments, it was shown that most of the enzyme was recovered during the first extraction. The procedure adopted increased the efficiency of endoglucanase extraction by 70%, emphasizing the importance of selection of suitable operational conditions during SSF processes.

Modelling of solid‐state fermentation over wide operational range for application in process optimization

“…Mitchell et al [6] suggested the use of a fourth-order polynomial to estimate some model parameters, which was used by Casciatori et al [29] Nevertheless, the large number of experiments required would be excessive. [31] All the experimental respiration profiles were within the confidence intervals (Figure 2), but this was not the case for all the enzymatic production profiles, as observed in the 40 8C endoglucanase production (Figure 2a). It should be noted that production variability is an inherent feature of biological processes.…”

“…Considering the results presented here, the present technique is a simpler option capable of representing the process, within the range of operational conditions considered. [31] All other enzymatic production data were within a 95 % confidence interval, despite some outliers, based on the t-student distribution. As examples, a variation of 12.5 % was observed between duplicates in the case of protease production, [30] while a AE20 % variation was found for endoglucanase production.…”

Solid-State Fermentation as a Novel Paradigm for Organic Waste Valorization: A Review

“…Dhillon et al [208] achieved higher citric acid extraction from the SSF process using response surface methodology involving process parameters such as extraction time, agitation rate, and solvent volume. Solid-liquid ratio, solvent or buffer type, pH, temperature, stirring rate, repeated extraction, and extraction time are process parameters that also have been studied to optimize the extraction of products from SSF [209][210][211][212][213][214]. However, in these studies usually a small amount of solid substrate ranging from 1-20 g in a shake flask was used for the extraction, and only some of them reported the extraction using the whole substrate fermented (in kg) with the aim of knowing the total recovery of the product [20].…”

Production of Cellulase from Bacillus subtilis under Solid- State Fermentation Using Fiber Wastes of Palmyra Palm

“…Pellet was discarded and the supernatant was stored which was taken as a crude enzyme. A cell free culture supernatant was a crude enzyme stored at 4°C and it was taken for cellulase assay tests (Pirota et al, 2013).…”