Reducing Bacterial Contamination in Fuel Ethanol Fermentations by Ozone Treatment of Uncooked Corn Mash

Ozonation of uncooked corn mash from the POET BPX process was investigated as a potential disinfection method for reducing bacterial contamination prior to ethanol fermentation. Corn mash (200 g) was prepared from POET ground corn and POET corn slurry and was ozonated in 250 mL polypropylene bottles. Lactic and acetic acid levels were monitored daily during the fermentation of ozonated, aerated, and nontreated corn mash samples to evaluate bacterial activity. Glycerol and ethanol contents of fermentation samples were checked daily to assess yeast activity. No yeast supplementation, no addition of other antimicrobial agents (such as antibiotics), and spiking with a common lactic acid bacterium found in corn ethanol plants,Lactobacillus plantarum, amplified the treatment effects. The laboratory-scale ozone dosages ranged from 26–188 mg/L, with very low estimated costs of $0.0008–0.006/gal ($0.21–1.6/m3) of ethanol. Ozonation was found to decrease the initial pH of ground corn mash samples, which could reduce the sulfuric acid required to adjust the pH prior to ethanol fermentation. Lactic and acetic acid levels tended to be lower for samples subjected to increasing ozone dosages, indicating less bacterial activity. The lower ozone dosages in the range applied achieved higher ethanol yields. Preliminary experiments on ozonating POET corn slurry at low ozone dosages were not as effective as using POET ground corn, possibly because corn slurry samples contained recycled antimicrobials from the backset. The data suggest additional dissolved and suspended organic materials from the backset consumed the ozone or shielded the bacteria.Reprinted with permission from J. Agric. Food Chem., 2015, 63 (21), pp 5239–5248. doi: 10.1021/acs.jafc.5b00563. Copyright 2015 American Chemical Society.</p

Prebiotics and Dietary Fibers from Food Processing By-Products

The abundance of agricultural wastes or by-products from industrial and domesti- Q1 cated food processing is the main cause of environment problems. These by-products are generally managed by disposal or even sold at a cheaper price. Disposal of these underutilized by-products are commonly done in inappropriate ways, i.e. discharge effluent into rivers or by burning in the open, which may cause air and water pollutions. Presently, scientific investigation on the benefits or functional properties of waste and by-products from industrial food processing, which produces a large amount of by-products, is necessary in the search for possible ways for their utilization (Vanesa et al., 2011). Three main groups of by-product from food processing, classified according to their main chemical compositions, are carbohydrate and dietary fibers, protein and lipids. The most common by-products are generated by the food industry, in particular the beverage, starch and flour industries. These items are classified under carbohydrate and dietary fiber groups. They are further divided into four sub-groups: monosaccharides, disaccharides, oligosaccharides and polysaccharides. Dietary fibers are a class of non-starch polysaccharides (i.e. cellulose, dextrins, chitins, pectins, β-glucans and waxes) and lignin, which are able to modulate the transit time through the gut. Thus, it provides similar beneficial effects to those of inulin-type fructans. These compounds are commonly found in many foods such as cereal, nuts etc. They are also partially susceptible to bacterial fermentation and may induce changes in bacterial populations, particularly in the numerous bifidobacteria and lactobacilli. These soluble dietary fibers have been shown to exert additional beneficial effects, for instance by improving gut barrier function in vitro and in vivo, which could be partially a consequence of their effect on the microflora composition (Laparra and Sanz, 2010)

Utilization of dry distillers grains and charcoal as nitrogen fertilizer in corn

Citation: Shroyer, K. J., S. A. Staggenborg, and J. L. Propheter. “Utilization of Dry Distillers Grains and Charcoal as Nitrogen Fertilizer in Corn.” Agronomy Journal 103, no. 5 (2011): 1321–28. https://doi.org/10.2134/agronj2010.0447.Increasing bio-energy production will result in increased by-products which will need proper disposal methods to prevent economic and/or ecological problems. Land application has potential for disposal and/or nutrient cycling if these by-products have crop nutritive value. Our objective was to compare the fertilizer effects of two by-products of bio-energy production, dry distillers grains with solubles (DDGs) and charcoal with urea in corn (Zea mays L.) and evaluate nutrient uptake. Treatments were DDGs under no-till and tilled at four location-years and charcoal under no-till and tilled at three location-years. No-till urea was used as a baseline at all location-years. Nitrogen rates ranged from 0 to 180 kg N ha[superscript]−1. All materials were spring applied before tillage and planting. Corn yields for DDGs and urea were similar across tillage treatments and locations. Corn yields over all charcoal rates and tillage treatments were the same as 0 kg N ha[superscript]−1. The charcoal, because of immobilization or lack of decomposition, did not contribute to the corn N nutrition. Neither material showed any negative effects on the corn yields. Stalk N, P, K, and grain N followed expected trends and had few effects compared with those from urea. Land application of DDGs and charcoal has merit for disposal/N cycling with DDGs being preferred for its N contribution