Waste Bread as a Biomass Source: Optimization of Enzymatic Hydrolysis and Relation between Rheological Behavior and Glucose Yield
- 366 Downloads
Amongst the many forms of food waste, bread is a major contributor to the problem. Two aims of this research investigate waste breads potential of being a bioresource for the production of fermentable sugars which are precursor of valuable bioproducts by fermentation process: finding optimum substrate, water and enzyme ratio to produce the highest amount of fermentable sugars and investigating the rheological behavior of the system during hydrolysis. Two stage waste bread hydrolysis was performed with enzymes α-amylase and amyloglucosiades and response surface methodology was used to optimize substrate, water and enzyme ratio. Discovery Hybrid Rheometer-2 (TA Instruments) fitted with a parallel-plate geometry was used to investigate steady flow viscosity of the slurry during hydrolysis. 99 % of theoretical maximum glucose yield, a main fermentable sugar, is achieved by optimizing enzymatic hydrolysis conditions of waste bread at liquefaction and saccharification stages. Just after the addition of α-amylase enzyme, substantial decrease is observed in viscosity and Casson apparent yield stress of the slurry. During saccharification stage, glucose yield increases dramatically while viscosity of the slurries is very low and does not change considerably. The results imply that utilizing high concentrations of waste bread as a feedstock to produce fermentation products offers economic benefits without causing high power consumption, excessive wear on equipment, and reduced conversion which are generally expected consequences for high-solid processing.
KeywordsFree feedstock Glucose yield Enzyme Viscosity
This research was supported with a Grant (TOVAG Project Number: 114O429) from The Scientific and Technological Research Council of Turkey (TUBITAK).
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no conflict of interest.
This study was Funded by The Scientific and Technological Research Council of Turkey (TUBITAK) with a Grant Number of 114O429.
- 3.Sukumaran, R.K., Pandey, A.: Ethanol from biomass. In: Biswas, S., Basak, P.R., Kaushik, N. (eds.) Biomass and Bioproducts-Emerging Trends, pp. 11–36. TIFAC, New Delhi (2009)Google Scholar
- 4.Taherzadeh, M.J., Karimi, K.: Enzymatic-based hydrolysis processes for ethanol. BioResources 2(4), 707–738 (2007)Google Scholar
- 5.Melikoglu, M., Webb, C.: Use of waste bread to produce fermentation products. In: Kosseva, M., Webb, C. (eds.) Food Industry Wastes: Assessment and Recuperation of Commodities. Academic Press, London (2013)Google Scholar
- 13.Dunaway, K.W., Dasari, R.K., Bennett, N.G., Eric Berson, R.: Characterization of changes in viscosity and insoluble solids content during enzymatic saccharification of pretreated corn stover slurries. Bioresour. Technol. 101(10), 3575–3582 (2010). doi: 10.1016/j.biortech.2009.12.071 CrossRefGoogle Scholar