Optimization of a Simultaneous Enzymatic Hydrolysis to Obtain a High-Glucose Slurry from Bread Waste

Abstract

Bread and bakery products are among the most discarded food products in the world. This work aims to investigate the potential use of wasted bread to obtain a high-glucose slurry. Simultaneous hydrolysis of wasted bread using α-amylase and glucoamylase was carried out performing liquefaction and saccharification at the same time. This process was compared with a traditional sequential hydrolysis. Temperature and pH conditions were optimized using a response surface design determining viscosity, reducing sugars and glucose concentration during the enzymatic processes. The optimal conditions of pH and temperature in the saccharification stage and the simultaneous hydrolysis were pretty similar. Results show that the slurry produced with simultaneous process had a similar glucose yield at 2 h, and at 4 h a yield higher than that obtained by the sequential method of 4 h and could reduce time and energy.

Bread waste – A potential feedstock for sustainable circular biorefineries

“…A simulatenous liquefaction and saccharifcation was carried out under optimal pH (4.51) and temperature (64.7 • C) resulting in 146.8 g/L glucose with 25 % solid loading. Whereas with the classical sequential liquefaction and saccharification the maximum glucose concentrations of 126.9 g/L was obtained with 25 % solid loading (Sigüenza-Andrés et al, 2022). Furthermore enzymatic hydrolysis can be carried out under lower temperatures in comparison to acid hydrolysis and does not involve any harsh chemicals and release of toxic molecules like acid hydrolysis.…”

“…The simultaneous enzymatic hydrolysis resulted in a glucose concentration of 112.1 g/L in 2 h compared to 126.9 g/L achieved in 4 h using the traditional two-step method. When the simultaneous process was prolonged for 4 h, 146.8 g/L glucose was accumulated (Sigüenza-Andrés et al, 2022). This simultaneous approach could result in a reduction of time, labour, energy and equipment costs for BW pre-processing and thus, the overall cost for glucose extraction from BW for fermentation.…”

Bread spoilage fungi as creators of α amylase using two types of wheat flour

“…The activity of microbial enzymes is critically affected by physical and nutritional factors as well as varies according to microbial creator (Deshmukh et al 2011). As mentioned in earlier studies, foods with high carbohydrate content in addition to other constituents make them ideal substrates for microbial development and enzyme synthesis (Ravindran and Jaiswal 2016;Sigüenza-Andrés et al 2022).…”

Characterization of a Fermented Beverage from Discarded Bread Flour Using Two Commercial Probiotics Starters

“…Several authors reached similar conclusions when using waste bread flour as a substrate for different microorganisms [ 9 , 10 , 11 ]. Prior to fermentation, the hydrolysis of starch using amylolytic enzymes is necessary in order to convert polysaccharides into fermentable sugars, facilitating bacterial growth, especially under optimized conditions [ 12 ].…”