Ethanol Production from Waste Potato Mash by Using Saccharomyces Cerevisiae

Abstract

Bio-ethanol is one of the energy sources that can be produced by renewable sources. Waste potato mash was chosen as a renewable carbon source for ethanol fermentation because it is relatively inexpensive compared with other feedstock considered as food sources. However, a pretreatment process is needed: specifically, liquefaction and saccharification processes are needed to convert starch of potato into fermentable sugars before ethanol fermentation. In this study, hydrolysis of waste potato mash and growth parameters of the ethanol fermentation were optimized to obtain maximum ethanol production. In order to obtain maximum glucose conversions, the relationship among parameters of the liquefaction and saccharification process was investigated by a response surface method. The optimum combination of temperature, dose of enzyme (α-amylase) and amount of waste potato mash was 95 °C, 1 mL of enzyme (18.8 mg protein/mL) and 4.04 g dry-weight/100 mL DI water, with a 68.86% loss in dry weight for liquefaction. For saccharification, temperature, dose of enzyme and saccharification time were optimized and optimum condition was determined as 60 °C-72 h-0.8 mL (300 Unit/mL) of amyloglucosidase combination, yielded 34.9 g/L glucose. After optimization of hydrolysis of the waste potato mash, ethanol fermentation was studied. Effects of pH and inoculum size were evaluated to obtain maximum ethanol. Results showed that pH of 5.5 and 3% OPEN ACCESSAppl. Sci. 2012, 2 739 inolculum size were optimum pH and inoculum size, respectively for maximum ethanol concentration and production rate. The maximum bio-ethanol production rate was obtained at the optimum conditions of 30.99 g/L ethanol. Since yeast extract is not the most economical nitrogen source, four animal-based substitutes (poultry meal, hull and fines mix, feather meal, and meat and bone meal) were evaluated to determine an economical alternative nitrogen source to yeast extract. Poultry meal and feather meal were able to produce 35 g/L and 32.9 g/L ethanol, respectively, which is higher than yeast extract (30.8 g/L). In conclusion, waste potato mash was found as a promising carbon source for ethanol fermentation with alternate nitrogen sources.

Acid Liquefaction of Potato (Solanum tuberosum) and Sweet Potato (Ipomoea batatas) Cultivars Peels – Pre-Screening of Antioxidant Activity/Total Phenolic and Sugar Contents

“…To use this waste as only livestock feed leads to the loss of raw material with considerable economic potential (Wu 2016). The main components of PPW are usually water, starch, cellulose, hemicellulose, fermentable sugars, lignin, proteins, polyphenols, and alkaloids (Izmirlioglu and Demirci 2012;Khawla et al 2014;Chintagunta et al 2016;Guechi and Hamdaoui 2016). Thus, this residue can potentially be utilized as feedstock for biorefineries and for the production of value-added products.…”

Kinetic Modeling and Techno-economic Feasibility of Ethanol Production From Carob Extract Based Medium in Biofilm Reactor

“…At stationary phase, dX/dt = 0 and X = X max . β = (dP/dt) stationary X max (10) The product (P) is obtained as a function of time from Equation (9) as follows (Equation 11).…”

“…Ethanol, a two-carbon aliphatic alcohol, can be produced from various renewable carbon resources such as rice hulls [1], tea processing wastes [2,3], carob pods [4][5][6][7], rice straw [8], barley husk, wheat bran, rye bran [9], waste potato mash [10][11][12], sugarcane [13], corn grain [14]. Among them, carob has been suggested to be an attractive raw material in the production of bioethanol from renewable sources due to its high carbohydrate content including sucrose, glucose, and fructose [5].…”

Fermentation optimization for a probiotic local northeastern Indian rice beer and application to local cassava and plantain beer production

“…It is widely used in preparing traditional fermented products in Asia. Yeasts are the most commonly used microorganisms for ethanol fermentation and Saccharomyces cerevisiae is one of the best-known ethanol producers (12). Lactobacillus plantarum are lactic acid bacteria frequently occurring in fermented foods of plant origin.…”