Search Results (12)

Acid oil produced from the acidulation of soapstock was investigated as a feedstock for producing a glycolipid biosurfactant, manosylerithritol lipid (MEL), by microbial fermentation. Fermentation with the optimized acid oil substrate concentration of 200 g L⁻¹ resulted in 3.89 g L⁻¹ of MEL. To enhance productivity, the titer MEL was produced by a multistage fermentation process with the periodic addition of 20–50 g L⁻¹ substrate after the stationary phase of the culture. The repeated substrate feeding marginally enhanced the MEL titer up to 5.56 g L⁻¹. The MEL from the culture broth was recovered by solvent extraction at different pH levels. Among the solvents tested, ethyl acetate: acetonitrile (9:1) demonstrated a higher partition coefficient value of 3.1 in acidic conditions with 75.6% MEL recovery. The MEL produced by using acid oil as feedstock has significant surface-active properties, measuring 2.8 × 10⁻⁶ M in critical micelle concentration with 29.3 mN m⁻¹ surface tension. Full article

The global trend towards net-zero carbon emissions from burning fuels in combustion engines alerts us to the alternative role of biodiesel. The manufacturing cost of biodiesel hinders the fast development of various types of biofuels. Feedstock cost is one of the major determining factors of biodiesel cost and thus the extent of its competitiveness in the fuel market with other available alternative fuels or fossil fuels. Some low-cost feedstocks such as high-acid oil, which is produced from the acidifying processes of soybean soapstock, frequently contain high contents of free fatty acids (FFAs) and water. Hence, those feedstocks cannot be used to produce biodiesel through strong alkaline catalyst transesterification on an industrial scale. In contrast, the water can be converted to hydroxyl radicals to enhance the formation of esters from the dissociation of the FFA in a supercritical reacting tank. Hence, cheap high-acid oils containing high amounts of water and FFAs were used to produce biodiesel through a supercritical transesterification reaction system. The engine emission characteristics of using the biodiesel produced in this study were analyzed and compared with those of commercial biodiesel and super-low sulfur diesel (SLSD). A naturally aspirated, direct-injection, four-stroke, four-cylinder marine diesel engine associated with an eddy-current dynamometer was used to carry out the engine emission measurement. In comparison with super-low sulfur diesel (SLSD), the biodiesel had lower CO₂ and CO emissions and black smoke opacity but higher emissions of O₂ and NO_x. The higher engine speed caused lower emissions of O₂ and NO_x but higher CO₂ emissions. The supercritical-transesterification biodiesel appeared to be a competitive alternative fuel to fossil diesel. Full article

Due to the increasing use and accumulation of petrochemical plastics in the environment and the rapid depletion of natural resources, microbial polyhydroxyalkanoates have great potential to replace them. This study provides new insights in the field of obtaining of polyhydroxyalkanoates (PHAs) from endophytic bacterial strains and applying them as potential biocontrol agents against postharvest diseases of apples. Two strains—Pseudomonas flavescens D5 and Bacillus aerophilus A2—accumulated PHAs in amounts ranging from 2.77 to 5.9 g L⁻¹. The potential to use low-cost substrates such as beet molasses and soapstock for PHA accumulation was shown. The PHAs produced by the Ps. flavescens D5 strain had pronounced antagonistic activity against Penicillium expansum (antifungal property = 62.98–73.08%). The use of PHAs as biocontrol agents significantly reduced the severity of apple blue mold, especially in the preventive treatment option. Full article

The use of fossil fuels (methane, oil, etc.) is undergoing an unprecedented crisis now. There is the urgent need to search for alternative energy sources. A wide range of degraded organic materials can be effectively used to provide energy together with environmental protection. Soapstock is a hazardous waste containing a high concentration of toxic organic compounds of man-made origin (fatty acids, surfactants, dyes, etc.). To prevent environmental contamination such substances require an effective treatment approach. The goal of the study was to isolate the adapted-to-fatty-acids methanogenic microbiome and investigate the patterns of sodium acetate and soapstock degradation with simultaneous biomethane synthesis. The effectiveness of the degradation of sodium acetate and soapstock by non-adapted and adapted microbiomes was evaluated by decreasing the concentration of dissolved organic compounds. The effectiveness of the fermentation process was determined by the biogas (mixture of CH₄ and CO₂) yield. The most effective degradation occurred in the variant with sodium acetate and adapted methanogens and amounted to 77.9%. In other variants, the patterns and the efficiency of purification were similar ranging from 60.6 to 68.0%. The biomethane was mostly synthesized by adapted methanogens on the soapstock and sodium acetate as substrates. Thus, the CH₄ yield was 368.4 L/kg of dissolved organic compounds or 127.5 L/kg of soapstock. The results of this study demonstrated the potential of methanogenic microorganisms in the biodegradation of soapstock with simultaneous biogas synthesis. The results can serve as a basis to reduce the reliance on fossil fuels by generating biomethane via the fermentation of toxic organics. Full article

The over-enrichment of phosphorus in waste streams can lead to eutrophication and oxygen limitations for aquatic life. To understand the release of phosphorus from a soybean processing facility, it is imperative to track the flow of phosphorus in different streams during the processing of soybeans. The objective of the study is to develop process simulation models to study the flow of phosphorus in the soy-biodiesel process and evaluate strategies to mitigate phosphorus release by recovering phosphorous from soapstock and wastewater. Since most of the P is found in soybean meal, the processing of which releases phosphorus, a third case of lecithin recovery was also studied to reduce the amount of phosphorous in soybean meal. It was observed that phosphorus can be economically recovered from the soapstock, as well as the wastewater stream, with an estimated operating cost of USD 1.65 and 3.62 per kg of phosphorous recovered, respectively. The phosphorus recovered from both streams can be potentially applied as fertilizer to more than 13,000 acres of corn or 96,000 acres of soybean, respectively. The lecithin recovery case was found to have the highest revenue, and it led to a 54% reduction in phosphorous during soybean meal processing. Full article

This study investigated acid splitting wastewater (ASW) and interphase (IF) from soapstock splitting, as well as matter organic non glycerol (MONG) from glycerol processing, as potential substrates for biogas production. Batch and semicontinuous thermophilic anaerobic digestion experiments were conducted, and the substrates were preliminary treated using commercial enzymes kindly delivered by Novozymes A/C. The greatest enhancement in the batch digestion efficiency was achieved when three preparations; EversaTransform, NovoShape, and Lecitase were applied in the hydrolysis stage, which resulted in the maximum methane yields of 937 NL/kg VS and 915 NL/kg VS obtained from IF and MONG, respectively. The co-digestion of 68% ASW, 16% IF, and 16% MONG (wet weight basis) performed at an organic loading rate (OLR) of 1.5 kg VS/m³/day provided an average methane yield of 515 NLCH₄/kg VS_added and a volatile solid reduction of nearly 95%. A relatively high concentration of sulfates in the feed did not significantly affect the digestion performance but resulted in an increased hydrogen sulfide concentration in the biogas with the peak of 4000 ppm. Full article

The review will discuss the methods that have been optimized so far for the enzymatic hydrolysis of soapstock into enriched mixtures of free fatty acids, in order to offer a sustainable alternative to the procedure which is currently employed at the industrial level for converting soapstock into the by-product known as acid oil (or olein, i.e., free fatty acids removed from raw vegetable oil, dissolved in residual triglycerides). The further biocatalyzed manipulation of soapstock or of the corresponding acid oil for the production of biodiesel and fine chemicals (surfactants, plasticizers, and additives) will be described, with specific attention given to processes performed in continuous flow mode. The valorization of soapstock as carbon source in industrial lipase production will be also considered. Full article

Recent research focuses on new biodiesel production and purification technologies that seek a carbon-neutral footprint, as well as cheap, renewable and abundant raw materials that do not compete with the demand for food. Then, many attractive alternatives arise due to their availability or low-cost, such as used cooking oil, Jatropha oil (non-edible) or byproducts of vegetable oil refineries. Due to their composition and the presence of moisture, these oils may need a pretreatment to reach the established conditions to be used in the biodiesel production process so that the final product complies with the international quality standards. In this work, a solid catalyst based on 10 wt % sodium oxide supported on mesoporous silica SBA-15, was employed in the transesterification of different feedstocks (commercial sunflower and soybean oil, used cooking oil, acid oil from soapstock and Jatropha hieronymi oil) with absolute methanol in the following reaction conditions—2–8 wt % catalyst, 14:1 methanol to oil molar ratio, 60 °C, vigorous magnetic stirring and 5 h of reaction. In this way, first- and second-generation biodiesel was obtained through heterogeneous catalysis with methyl ester yields between 52 and 97 wt %, depending on the free fatty acid content and the moisture content of the oils. Full article

Enzymatic hydroesterification is a heterogeneous catalyzed process suitable for the conversion of low-cost feedstocks in biodiesel production, namely, because of its tolerance to high free fatty acid contents. The current study describes the use of Fourier transform infrared spectroscopy (FTIR) to monitor biodiesel production using enzymatic hydroesterification and, as raw materials, acid oil from soapstock and olive pomace oil. Acid oil (~34 wt.% FFA) and olive pomace oil (~50 wt.% FFA) were first hydrolyzed (35 °C, 24 h, 200 rpm, 3 wt.% of lipase from Thermomyces lanuginosus, and 1:0.5 water:oil ratio, w:w), and then enzymatic esterification was performed (35 °C, 7 h, 200 rpm, 2 wt.% of lipase from Thermomyces lanuginosus, and 2:1 molar ratio of methanol to acid). FTIR analyses were conducted on the products using a Jasco FT/IR-4100 with a scanning range of 4000–650 cm⁻¹ at 4 cm⁻¹ spectral resolution and 54 scans. For free fatty acid (FFA) quantification, the C=O band at 1708 cm^–1 was used, corresponding to the carboxylic acid, whereas for fatty acid methyl ester (FAME) quantification, the peak corresponding to C=O at 1746 cm⁻¹ was considered, which corresponded to the ester. The results were calibrated using volumetric titration and gas chromatography analyses, concerning FFA and FAME quantification, respectively. The best conditions for analysis were determined, and a calibration method was established. FTIR has shown to be a simple, fast, and clean technique suitable to monitor hydroesterification of low-cost feedstocks. Full article

The buriti palm (Mauritia flexuosa) is a palm tree widely distributed throughout tropical South America. The oil extracted from the fruits of this palm tree is rich in natural antioxidants. The by-products obtained from the buriti palm have social and economic importance as well, hence the interest in adding value to the residue left from refining this oil to obtain biofuel. The process of methyl esters production from the buriti oil soapstock was optimized considering acidulation and esterification. The effect of the molar ratio of sulfuric acid (H₂SO₄) to soapstock in the range from 0.6 to 1.0 and the reaction time (30–90 min) were analyzed. The best conditions for acidulation were molar ratio 0.8 and reaction time of 60 min. Next, the esterification of the fatty acids obtained was performed using methanol and H₂SO₄ as catalyst. The effects of the molar ratio (9:1–27:1), percentage of catalyst (2–6%) and reaction time (1–14 h) were investigated. The best reaction conditions were: 18:1 molar ratio, 4% catalyst and 14 h reaction time, which resulted in a yield of 92% and a conversion of 99.9%. All the key biodiesel physicochemical characterizations were within the parameters established by the Brazilian standard. The biodiesel obtained presented high ester content (96.6%) and oxidative stability (16.1 h). Full article

Ferulic acid (FA) is widely used as an antioxidant, e.g., as a Ultraviolet (UV) protectant in cosmetics and in various medical applications. It has been produced by the hydrolysis of γ-oryzanol found in rice bran oil soapstock. In this study, the base-catalyzed, homogenous hydrolysis of γ-oryzanol was conducted using various ratios of potassium hydroxide (KOH) to γ-oryzanol, initial concentrations of γ-oryzanol in the reaction mixture, and ratios of ethanol (EtOH) (as cosolvent)/ethyl acetate (EtOAc) (γ-oryzanol solution). Acceleration of the reaction using a planar type of ultrasound sonicator (78 and 130 kHz) at different reaction temperatures was explored. By using a heating method, the 80% yield of FA was attained at 75 °C in 4 h under homogeneous conditions (initial concentration of γ-oryzanol 12 mg/mL, the KOH/γ-oryzanol ratio (wt/wt) 10/1, and EtOH/EtOAc ratio (v/v) 5/1). With the assistance of 78 and 130 kHz irradiation, the yields reached 90%. The heating method was applied for the γ-oryzanol-containing extract prepared from rice bran oil soapstock. From soapstock, the 74.3% yield of FA was obtained, but 20% of the trans-FA in the reaction mixture was transformed into cis-form within one month. Full article

A supercritical methanol transesterification method was applied to produce biodiesel from the high-acid oil of soybean soapstock. The fuel properties of biodiesel produced with various molar ratios of methanol to raw oil were analyzed and compared in this experimental study. Oleic acid (C18:1), linoleic acid (C18:2), and palmitic acid (C16:0) were the three main compounds in the high-acid oil-biodiesel. The saturated fatty acid content of the high-acid oil increased significantly due to the supercritical-methanol transesterification reaction. The fuel characteristics of the resulting high-acid oil, including the specific gravity and kinematic viscosity, were also greatly improved. The saturated fatty acid content of the biodiesel produced from the high-acid oil was higher than that of biodiesel from waste cooking oil produced by the subcritical transesterification using a strongly alkaline catalyst. The high-acid oil-biodiesel that was produced with a molar ratio of methanol to raw oil of 42 had the best fuel properties, including a higher distillation temperature and cetane index and a lower kinematic viscosity and water content, among the biodiesels with different molar ratios. Full article