Effect Of Crude Glycerol Research Articles

Bioconversions of Biodiesel-Derived Glycerol into Sugar Alcohols by Newly Isolated Wild-Type Yarrowia lipolytica Strains

The utilization of crude glycerol, generated as a by-product from the biodiesel production process, for the production of high value-added products represents an opportunity to overcome the negative impact of low glycerol prices in the biodiesel industry. In this study, the biochemical behavior of Yarrowia lipolytica strains FMCC Y-74 and FMCC Y-75 was investigated using glycerol as a carbon source. Initially, the effect of pH value (3.0–7.0) was examined to produce polyols, intracellular lipids, and polysaccharides. At low pH values (initial pH 3.0–5.0), significant mannitol production was recorded. The highest mannitol production (19.64 g L−1) was obtained by Y. lipolytica FMCC Y-74 at pH = 3.0. At pH values ranging between 5.0 and 6.0, intracellular polysaccharides synthesis was favored, while polyols production was suppressed. Subsequently, the effect of crude glycerol and its concentration on polyols production was studied. Y. lipolytica FMCC Y-74 showed high tolerance to impurities of crude glycerol. Initial substrate concentrations influence polyols production and distribution with a metabolic shift toward erythritol production being observed when the initial glycerol concentration (Gly0) increased. The highest total polyols production (=56.64 g L−1) was obtained at Gly0 adjusted to ≈120 g L−1. The highest polyols conversion yield (0.59 g g−1) and productivity (4.36 g L−1 d−1) were reached at Gly0 = 80 g L−1. In fed-batch intermittent fermentation with glycerol concentration remaining ≤60 g L−1, the metabolism was shifted toward mannitol biosynthesis, which was the main polyol produced in significant quantities (=36.84 g L−1) with a corresponding conversion yield of 0.51 g g−1.

Effects of Lipase Addition, Hydrothermal Processing, Their Combination, and Co-Digestion with Crude Glycerol on Food Waste Anaerobic Digestion

To enhance anaerobic fermentation during food waste (FW) digestion, pretreatments can be applied or the FW can be co-digested with other waste. In this study, lipase addition (LA), hydrothermal pretreatment (HTP), and a combination of both methods (HL) were applied to hydrolyze organic matter in FW. Furthermore, the effects of crude glycerol (CG), which provided 5%, 10%, and 15% of the volatile solids (VS) as co-substrate (denoted as CG5, CG10, and CG15, respectively), on the anaerobic digestion of FW were assessed. With an increasing proportion of CG in the co-digestion experiment, CG10 showed higher methane production, while CG15 negatively affected the anaerobic digestion (AD) performance owing to propionic acid accumulation acidifying the reactors and inhibiting methanogen growth. As the pretreatments partially decomposed hard-to-degrade substances in advance, pretreated FW showed a stronger methane production ability compared with raw FW, especially using the HL method, which was significantly better than co-digestion. HL pretreatment was shown to be a promising option for enhancing the methane potential value (1.773 NL CH4/g VS) according to the modified Gompertz model.

Pelletizing of Colombian agro-industrial biomasses with crude glycerol

The effect of crude glycerol (G) on the pelletizing process and the quality of biomasses pellets were evaluated. Pellets were made of three types of agro-industrial biomasses typical of tropical countries: Sugarcane bagasse (SCB), Coffee Husk (CH) and Rice Husk (RH). Mixtures of water and glycerol were used as a binder. It was found that, with the addition of crude glycerin, the linkages between biomass particles for formation of pellets is made easier. However, this addition causes a reduction of the compaction degree since it acts as a lubricant between the biomass and the pelletization die, which produces the weakening of the solid to solid interaction. For CH and SCB particles, due to its shape and soft structure, pelletizing is not significantly affected by the biomass particle size variation, whereas in the case of small RH particles, the presence of a binder favors pelletizing. A brief dissertation about the aggregation mechanisms those were favored in each biomass type was carried out. A multi-criteria methodology was implemented by which it was possible to select the optimal conditions of pelletizing for each biomass.

Hydrogen Production by Anaerobic Digestion of Crude Glycerol from Biodiesel Fuel Manufacturing Process – Part I. Inoculum Characteristics and the Effect of Crude Glycerol

In order to utilize crude glycerol, a byproduct from biodiesel fuel production, its conversion through anaerobic fermentation was examined. It was found that crude glycerol enhances hydrogen production while suppressing methane fermentation. Characteristics of the anaerobic fermentation with crude glycerol were examined. There existed an optimum crude glycerol concentration when it was digested with an inoculum of cattle excrement origin.
 Keywords: Biodiesel fuel, Crude glycerol, Anaerobic digestion, Hydrogen fermentation

Glycerol on Lipid Enhancement and FAME Characterization in Algae for Raw Material of Biodiesel

To reduce the cost of media components and consecutively enhance the amount of lipid formation, the effect of crude glycerol on Euglena gracilis is reported for the first time. Presently, E. gracilis has been chosen because of excellent capability of its growth and lipid synthesis in mixotrophic culture condition on organic carbon sources (Glucose and Glycerol). Biochemical composition of the cell in presence of both organic carbon sources were compared in mixotrophic condition. Glycerol was selected as most suitable carbon source and the highest biomass concentration of 2.63 g L -1 and lipid accumulation of 27.64 % were observed. The effect of biodiesel derived crude glycerol on the growth of E. gracilis was found very positive. A significant increase in lipid accumulation (49.46%) was noticed in presence of crude glycerol by optimizing concentration and other culture parameters. Fatty acid methyl esters (FAMEs) produced from lipid biomolecules by following transesterification reaction, were analysed through GC-MS. FAMEs governed by 93.458% C16-C18 fatty acids with appropriate quantities of Saturated fatty acids (SFA) and Unsaturated fatty acids (UFA). Several requisite fuel properties were estimated and found to be in accordance with American and European biodiesel standards. Hence, this study focuses the improved lipid synthesis in E. gracilis utilizing crude glycerol for the preparation of raw biodiesel and it supports biorefinery approach.

Effect of crude glycerol from South African biodiesel production on growth, carcass characteristics and pork quality of pigs

A study was carried out to evaluate the effects of dietary inclusion of crude glycerol as a partial replacement of maize at 50 g/kg and 100 g/kg in pig grower diets. Three experimental diets were formulated, a control (CN) and two diets containing 50 g/kg (low glycerol (LG)) and 100 g/kg (high glycerol (HG)) glycerol. The experimental diets were fed in a growth and carcass evaluation study to 60 Large White crossbred pigs (30 males and 30 females) weighing 21 ± 1.6 kg. There were no differences between the glycerol inclusion levels in daily gain, feed intake and feed conversion ratio and carcass traits of the pigs. Gilts had a higher dressing percentage and lower backfat thickness than boars. They also had shorter carcasses and a lower drip loss percentage than boars. There were no differences in thawing, drip, evaporation and total cooking losses of pork loin chops between treatments. It was concluded that crude glycerol can be included up to 100 g/kg in grower pig diets without any negative effects on pig performance.Keywords: Energy, digestibility, fatty acids, biofuel, cooking characteristics

Effects of increasing crude glycerol and dried distillers grains with solubles on growth performance, carcass characteristics, and carcass fat quality of finishing pigs1,2

This study was conducted to determine the effects of dietary crude glycerol and dried distillers grains with solubles (DDGS) on growing-finishing pig performance, carcass characteristics, and carcass fat quality. We hypothesized that because dietary crude glycerol has been observed to increase carcass SFA, it might ameliorate the negative effects of DDGS on fat quality. The 97-d study was conducted at a commercial swine research facility in southwestern Minnesota with 1,160 barrows (initial BW = 31.0 ± 1.1 kg). Pigs were blocked by initial BW, and pens were randomly allotted to 1 of 6 dietary treatments with 7 replications per treatment. Treatments were arranged in a 2 × 3 factorial with main effects of crude glycerol (0, 2.5, or 5%) and DDGS (0 or 20%). All corn-soybean meal-based diets contained 3% added fat (choice white grease). There were no glycerol × DDGS interactions for any response criteria evaluated. Increasing dietary glycerol did not affect finishing pig growth performance. Adding 20% DDGS to the diet did not affect ADG; however, finishing pigs fed diets with added DDGS had greater (2.47 vs. 2.41 kg/d; P = 0.02) ADFI and poorer (0.39 vs. 0.40; P = 0.01) G:F than pigs not fed DDGS. Feeding increasing dietary glycerol or 20% DDGS did not affect carcass characteristics. For carcass fat quality, feeding 20% DDGS resulted in decreased (P < 0.01) palmitic and oleic acids, total SFA and total MUFA, and increased (P < 0.01) linoleic, total PUFA, total unsaturated fatty acids, and iodine value in jowl fat, belly fat, and backfat. Increasing dietary crude glycerol increased myristic acid (linear, P < 0.05) and MUFA (quadratic, P < 0.05) in jowl fat and increased (quadratic, P < 0.05) oleic acid and MUFA in backfat. In conclusion, feeding 20% DDGS to finishing pigs increased ADFI, reduced G:F, and increased carcass fat iodine value, whereas feeding crude glycerol did not influence growth performance, carcass characteristics, and had a minor influence on fatty acids of carcass fat. Both of these biofuel coproducts can be used in combination without affecting finishing pig performance or carcass traits; however, feeding crude glycerol did not fully mitigate the increased unsaturation of carcass fat observed when feeding DDGS.

Inhibitory effect of crude glycerol on ethanol production by Enterobacter aerogenes

Inhibitory effect of crude glycerol on ethanol production by Enterobacter aerogenes

Evaluation of glycerol, a biodiesel coproduct, in grow-finish pig diets to support growth and pork quality1,2

Crossbred pigs (n = 216; BW = 31.3 ± 1.8 kg) were used to determine the effects of long- and short-term feeding of crude glycerol on growth performance, carcass traits, and pork quality of grow-finish pigs. Pigs were blocked by initial BW, and pens within blocks were assigned randomly to 1 of 3 dietary treatments (24 pens; 9 pigs/pen). Dietary treatments were control, a corn-soybean meal-based diet (CON); long-term, CON + 8% glycerol fed throughout the experiment (LT); and short-term, pigs fed CON for the first 6 wk followed by CON + 8% glycerol fed during the last 8 wk of the experiment (ShT). Pigs fed LT had greater (P < 0.05) ADG, whereas pigs fed ShT tended (P < 0.10) to grow faster than CON (CON = 0.962 kg/d, LT = 0.996 kg/d, and ShT = 0.992 kg/d; SE = 0.01). Pigs assigned to LT had greater (P < 0.05) ADFI compared with CON, whereas ShT-fed pigs had similar ADFI to CON (CON = 2.78 kg/d, LT = 2.93 kg/d, and ShT = 2.86 kg/d; SE = 0.03). Gain:feed tended (P < 0.10) to be greater for CON- and ShT-fed pigs compared with LT-fed pigs (CON = 0.346, LT = 0.339, and ShT = 0.346; SE = 0.002). Hot carcass weight was greater (P < 0.05) for LT-fed pigs compared with CON, whereas ShT-fed pigs had HCW similar to both LT- and CON-fed pigs (CON = 94.8 kg, LT = 97.5 kg, and ShT = 96.3 kg; SE = 0.90). Dressing percentage of CON-fed pigs was similar to both LT- and ShT-fed pigs, but LT-fed pigs tended to have greater (P = 0.06) dressing percentage than ShT-fed pigs (CON = 74.5%, LT = 74.9%, and ShT = 74.3%; SE = 0.16). Tenth-rib backfat (P = 0.26) and LM area (P = 0.17) were not affected by dietary treatment. There was a trend (P < 0.10) for LT-fed pigs to have a smaller fat-free lean percentage than CON-fed pigs (CON = 53.1%, LT = 52.26%, and ShT = 52.67%; SE = 0.25). Short-term glycerol feeding increased (P < 0.05) belly firmness compared with CON and had similar belly firmness compared with LT-fed pigs (CON = 29.46°, LT = 35.16°, and ST = 42.08°; SE = 3.07). Dietary treatment had no effect (P > 0.60) on pork quality of loins based on taste panel assessments. Feeding pigs 8% crude glycerol throughout the grow-finish period resulted in a 3% improvement in growth rate and a 2% depression in BW gain efficiency compared with CON diets. Grow-finish pigs fed diets containing 8% crude glycerol during the last 8 wk before slaughter achieved growth performance similar to pigs fed CON diets. Effects of crude glycerol on carcass traits seem to be limited to improvements in belly firmness with short-term feeding of glycerol.

Hydrothermal Conversion of Corn Cobs and Crude Glycerol

The effect of operating parameters including reaction temperature, retention time, and biomass content on bio-oil yield from hydrothermal conversion of corn cobs was investigated. The highest bio-oil yield of 23.9% on the basis of biomass dry weight was obtained at 305C, 20 min retention time, and 10% biomass content. At these conditions, the effect of crude glycerol on bio-oil yield and quality was studied. Bio-oil yield based on the total weight of corn cobs and crude glycerol remained almost constant at approximately 24% when the ratio of crude glycerol/corn cobs was below 3. When more crude glycerol was added, bio-oil yield dramatically increased to 36.3%. H2 molar percentage in the gas product increased from 11.1% to 27.5% as the crude glycerol/corn cobs ratio increased from 0 to 5. Bio-oil quality in terms of density and viscosity was also enhanced; however, oxygen content in bio-oil increased from 15.5% to 19.9%.

Enhanced methane and hydrogen production from municipal solid waste and agro-industrial by-products co-digested with crude glycerol

The effects of crude glycerol on the performance of single-stage anaerobic reactors treating different types of organic waste were examined. A reactor treating the organic fraction of municipal solid waste produced 1400 mL CH 4/d before the addition of glycerol and 2094 mL CH 4/d after the addition of glycerol. An enhanced methane production rate was also observed when a 1:4 mixture of olive mill wastewater and slaughterhouse wastewater was supplemented with crude glycerol. Specifically, by adding 1% v/v crude glycerol to the feed, the methane production rate increased from 479 mL/d to 1210 mL/d. The extra glycerol-COD added to the feed did not have a negative effect on the reactor performance in either case. Supplementation of the feed with crude glycerol also had a significant positive effect on anaerobic fermentation reactors. Hydrogen yield was 26 mmole H 2/g VS added and 15 mmole H 2/g VS added in a reactor treating the organic fraction of municipal solid waste and a 1:4 mixture of olive mill and slaughterhouse wastewater. The addition of crude glycerol to the feed enhanced hydrogen yield at 2.9 mmole H 2/g glycerol added and 0.7 mmole H 2/g glycerol added.

Effect of crude glycerol on pellet mill production and nursery pig growth performance1,2

The objective of this study was to determine the effects of diets containing crude glycerol on pellet mill production efficiency and nursery pig growth performance. In a pilot study, increasing crude glycerol (0, 3, 6, 9, 12, and 15%) in a corn-soybean meal diet was evaluated for pellet mill production efficiency. All diets were steam conditioned to 65.5 degrees C and pelleted through a pellet mill equipped with a die that had an effective thickness of 31.8 mm and holes 3.96 mm in diameter. Each diet was replicated by manufacturing a new batch of feed 3 times. Increasing crude glycerol increased both the standard (linear and quadratic, P < 0.01) and modified (linear, P < 0.01; quadratic, P </= 0.02) pellet durability indexes up to 9% with no further benefit thereafter. The addition of crude glycerol decreased (linear; P < 0.01) production rate (t/h) and production efficiency (kWh/t). In a 26-d growth assay, 182 pigs (initial BW, 11.0 +/- 1.3 kg; 5 or 6 pigs/pen) were fed 1 of 7 corn-soybean meal-based diets with no added soy oil or crude glycerol (control), the control diet with 3 or 6% added soy oil, 3 or 6% added crude glycerol, and 6 or 12% addition of a 50:50 (wt/wt) soy oil/crude glycerol blend with 5 pens/diet. The addition of crude glycerol lowered (P < 0. 01) delta temperature, amperage, motor load, and production efficiency. The addition of crude glycerol improved (P < 0.01) pellet durability compared with soy oil and the soy oil/crude glycerol blend treatments. Pigs fed increasing crude glycerol had increased (linear, P = 0.03) ADG. Average daily gain tended to increase with increasing soy oil (quadratic; P = 0.07) or the soy oil/crude glycerol blend (linear, P = 0.06). Adding crude glycerol to the diet did not affect G:F compared with the control. Gain:feed tended to increase with increasing soy oil (linear, P < 0.01; quadratic, P = 0.06) or the soy oil/crude glycerol blend (linear, P < 0.01; quadratic, P = 0.09). Nitrogen digestibility tended (P = 0.07) to decrease in pigs fed crude glycerol compared with pigs fed the soy oil treatments. Apparent digestibility of GE tended (P = 0.08) to be greater in the pigs fed soy oil compared with pigs fed the soy oil/crude glycerol blends. In conclusion, adding crude glycerol to the diet before pelleting increased pellet durability and improved feed mill production efficiency. The addition of 3 or 6% crude glycerol, soy oil, or a blend of soy oil and glycerol in diets for 11- to 27-kg pigs tended to increase ADG. For pigs fed crude glycerol, this was a result of increased ADFI, whereas, for pigs fed soy oil or the soy oil/crude glycerol, the response was a result of increased G:F.