Fermentation products from potato starch

Several carbohydrates such as corn and potato starch, molasses and whey can be used to produce lactic acid. Starch must fust be hydrolysed to glucose by enzymatic hydrolysis then fermentation is performed in the second stage. The choice of carbohydrate material depends upon its availability, and pretreatment is required before fermentation. We shall describe the bioprocess for the production of lactic acid from whey. 

The production of CDs via enzymatic reaction with starch has been recently reviewed (i 7). CGTase is an extracellular protein and is usually isolated as a crude mixture from the medium. This crude protein is used directly for industrial fermentations. The basic process involves standard enz3miatic fermentation, with careful attention to reaction temperature. All three CDs and some Unear oligosaccharides are normally produced. Yields are highly dependent on the source of starch substrate. Potato starch is normally used or an extract of potato starch is often added to other starches 18-19), The potato starch component(s) responsible for stimulating CD formation have not been determined. Low starch concentrations (5%-10%) are normally used industrially. Published yields are in the 50% - 80% conversion range. 

In countries where a strong environmental regulation for industrial wastewater exists, purification of waste streams from potato factories regarding both the fruit water and the pulp is required. Several attempts have been made to dehydrate the by-products and to utilize them for different purposes. Its high moisture content (80%) requires an expensive drying due to the problem of spoilage, if left untreated. The starch industry tries to sell as much pulp as possible as wet or partially dried cattle feed. However, the need for potato pulp by farmers is limited. Potato pulp is being used as cattle feed as well as a solid-state fermentation media for the production of different biomolecules. Conventional applications of potato pulp are listed in Table 16.2. 

Com symps [8029-434] (glucose symp, starch symp) are concentrated solutions of partially hydrolyzed starch containing dextrose, maltose, and higher molecular weight saccharides. In the United States, com symps are produced from com starch by acid and enzyme processes. Other starch sources such as wheat, rice, potato, and tapioca are used elsewhere depending on availability. Symps are generally sold in the form of viscous liquid products and vary in physical properties, eg, viscosity, humectancy, hygroscopicity, sweetness, and fermentability. 

An example of the efficiency of anion exchange chromatography is demonstrated by using cyclodextrines [110]. Depending on the number of glucose residues, one distinguishes between a-, / -, and y-cyclodextrin. Isolated from liquified potato starch after fermentation based on the enzyme system of Bac. macerans, they are constituents of pharmaceutical and cosmetic products. The separation in Fig. 3-114 reveals that the cyclodextrin retention cannot be correlated with its molecular weight. 

Most current commercial ethanol production is from the fermentation of sugar and starch crops. Yeast can rapidly convert sucrose to ethanol with a theoretical carbon conversion of 67%. The production of ethanol from corn grew to about 1.9 billion gallons in 2001. This accounted for 90% of the total ethanol production and an estimated 615 million bushels of corn (6.2% of total corn produced) were consumed. The remaining 10% of ethanol production was by fermentation of grain sorghum, barley, wheat, cheese whey, and potatoes. 

Fumaric acid production from starch hydrolysate by R. arrhizus NRRL 1526 was studied by Federici et al. [75] in a 3-1 stirred-tank fermentor with CaCO, and KOH/KCO3 as the neutralizing agent and CO2 source. The fermentation conditions for fumaric acid production by this fungus from potato flour has been optimized by Moresi et al. [76]. 

More specifically, these systems, whether operated in the conventional mode or as rotary units have been successfully utilized in applications such as the recovery of protein and lactose from cheese whey, separation of fermentation products, concentration of fluids foods and juices, manually operable sea water desalinators, recovery of starch from potato processing fluids, and processlng/separatlon of pharmaceutical and chemical mixtures. 

Natural media are often based on corn steep liquor, malt extract or potato extract. Corn steep liquor is a by-product from the preparation of starch from maize and is particularly useful as a source of nitrogen. In the initial studies on the development of the penicillin fermentation the addition of corn steep liquor to the medium produced a significant increase in the antibiotic titre. 

Biobased polymers are those made from natural or organic ingredients, such as starch from corn, potato, tapioca, rice, or wheat (Narayan 2006a, 201 lb). Biobased polymers can also be made from oils, such as palm seed, linseed, soy bean, or fermentation products, like polylactic acid (PEA), polyhydroxy alkanoate (PHA), and polyhydroxybutyrate (PHB). BPI World provides a listing of compostable plastic resins, bags, cutlery, and packaging (BPI World 2013). 

Outside of the use of cellulose for papermaking, starch is the most widely used plant-derived carbohydrate for non-food uses. Around 60 million tonnes of raw starch are produced per year for food and non-food uses. The US accounts for most of the world s production, utilising starch from maize, which accounts for over 80% of world production. The starch market in the US is driven by the large isoglucose sweetener market and now increasingly by the growing bioethanol market, which uses maize as a fermentation feedstock. Europe derives most of its starch from wheat and potatoes, which account for 8% and 5% of world starch production, respectively. The other main source of starch is cassava (tapioca), produced in South East Asia. Small amounts of oat, barley and rice are also exploited for starch production. Many edible beans are also rich in starches, but are not commonly exploited for non-food uses. 

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