This study investigated Chlorella's capacity to treat cheese whey (CW) effluent and produce a high-nutritional value biomass, by using a systematic sequential experimental design. Physicochemical ...analysis of CW revealed its high pollution load, characterized by elevated levels of lactose, phosphorus, and nitrogen, as well as high turbidity due to the presence of whey solids. Screening experiments demonstrated that trace mineral addition and continuous air supply are essential factors for Chlorella biomass production in CW (>800 mg·mL−1). Furthermore, whey solids did not hinder Chlorella growth, with notable biomass production observed even in undiluted CW, demonstrating this microalga's ability to adapt metabolically to the complex environment. Laboratory-scale photobioreactor experiments confirmed Chlorella's ability to produce biomass in CW, outperforming controls (>800 mg·mL−1). Bioremediation potential assessment exhibited significant reductions in organic pollutants (>14 g·L−1 COD), nitrogen (>400 mg·L−1), phosphorus (>140 mg·L−1) and sodium (>650 mg·L−1). CW solids were also removed with Chlorella harvesting (>99 %). Harvested algal biomass was enriched with proteins (>40 g·100 g−1), polyunsaturated fatty acids (>9 % TFA) and pigments, offering potential applications in nutraceutical and pharmaceutical industries. Overall, this study highlights Chlorella's efficacy in CW treatment and biomass valorization, offering a sustainable solution for dairy wastewater management while producing valuable resources.
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•A systematic sequential experimental design was developed for algal cultivation in CW.•Chlorella can produce biomass in CW with trace mineral addition and air supply.•Chlorella could remove significant amounts of lactose from CW.•Mixotrophy led to high yields of biomass.•Chlorella cultivation in CW increased the nutritional value of the whey solid fraction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Dark fermentation (DF), hydrothermal carbonization (HTC) and anaerobic digestion (AD) are applied, in different combinations, to cheese whey (CW), which is the liquid effluent from the precipitation ...and removal of milk casein during the cheese-making process. The aim and novelty of this research is to investigate the production of various biofuels (H2-rich gas, hydrochar and biogas) in cascade, according to the waste biorefinery concept. The simplest case is the direct AD of CW. The second investigated possibility is the preliminary HTC of CW, producing hydrochar, followed by the AD of the process water from which hydrochar is separated by filtration. The third possibility is based on DF of CW, followed by the AD of the fermentate (F) from DF. The final possibility is based on DF of CW, followed by HTC of the F, and then AD of the process water. Accordingly, the physical and chemical properties of CW, F, resulting hydrochar and process water (PW), and biomethane potentials of CW, F, and process waters are studied to determine the energy and carbon balances of all variants. In brief, the first variant, direct AD of CW, is believed to be the most energy efficient method.
•Cheese whey was studied by dark fermentation, hydrothermal carbonization, anaerobic digestion.•Various biofuels, H2-rich gas, hydrochar and biogas, were investigated in cascade.•Properties of cheese whey, fermentate, hydrochar and process water were studied.•Energy and carbon balances of all variants were determined.•Anaerobic digestion of cheese whey is the most energy efficient method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The widespread adoption of Poly(3-hydroxybutyrate) (PHB) encounters challenges due to its higher production costs compared to conventional plastics. To overcome this obstacle, this study investigates ...the use of low-cost raw materials and optimized production methods. Specifically, food processing byproducts such as corn germ and corn bran were utilized as solid substrates through solid-state fermentation, enriched with molasses and cheese whey. Employing the One Factor at a Time technique, we examined the effects of substrate composition, temperature, initial substrate moisture, molasses, and cheese whey on PHB production at the flask scale. Subsequently, experiments were conducted at the bioreactor scale to evaluate the influence of aeration. In flask-scale experiments, the highest PHB yield, reaching 4.1 (g/kg Initial Dry Weight Substrate) (IDWS) after 72 hours, was achieved using a substrate comprising a 1:1 mass ratio of corn germ to corn bran supplemented with 20 % (v/w) cheese whey. Furthermore, PHB production in a 0.5-L packed-bed bioreactor yielded a maximum of 8.4 (g/kg IDWS), indicating a more than 100 % increase in yield after 72 hours, with optimal results achieved at an aeration rate of 0.5 l/(kg IDWS. h).
•PHB was synthesized using a mixture of agricultural and food waste substrates.•The impact of operational variables on PHA production in SSF was determined.•Temperature, moisture, substrate composition and cheese whey affected on process.•SSF was scaled up to a packed-bed bioreactor to investigate aeration rate effect.•Maximum PHB production reached 8.4 (g/kg IDWS) using Cupriavidus necator.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Yeast’s beta-galactosidase is an intracellular enzyme, through which it is possible to determine in vivo its activity as a biocatalyst in the lactose hydrolysis. Permeabilization process was used for ...transforming the microorganisms cells into biocatalysts with an enhanced enzyme activity. The potential application of this enzyme technology in industrial process depends mainly on the enzyme activity. Beta-galactosidase enzyme that hydrolyzes lactose, for instance, is largely dependent on the reaction time and its stability under different physical conditions, such as pH, temperature and enzyme concentration. The objective of this study was to optimize the cellular permeabilization process of Kluyveromyces marxianus CCT 3172 and Saccharomyces fragilis CCT 7586 cultured in cheese whey for lactose hydrolysis. Box-Behnken design was carried out for cell permeabilization with three independent variables, ethanol concentration, permeabilization time and temperature. The best permeability conditions for K. marxianus CCT 3172 were 27% (v v-1) ethanol, 3 min at 20ºC, with specific enzymatic activity of 0.98 U mg-1. For S. fragilis CCT 7586, a specific enzymatic activity of 1.31 U mg-1 was achieved using 45% (v v-1) of ethanol, 17 min. of reaction under 17ºC. Thus, it was concluded that cellular permeabilization with ethanol is an efficient process to determine beta-galactosidase activity.
Cheese whey has relevant nutritional, health and functional properties that could address the dietary needs of a growing world population. Nevertheless, around 50% of whey produced globally is not ...reused in the food system. A significant role in cheese production is played by small and medium enterprises (SMEs) that process typical products labelled with a protected designation of origin (PDO), representing both the cultural heritage and the major economical resource of specific geographical regions.
This study is aimed at identifying the potential involvement of SMEs in the recycling of whey for food uses. Techno-economic analyses of whey recycling processes were reviewed to define efficient configurations and plant size. Safety and quality specifications for whey were then examined as well as traceability systems designed for improving transparency among the actors and stakeholders of the dairy supply chain.
The study led to conclude that a whey value chain could be built by various cheese SMEs and a stand-alone industrial unit for the downstream processing of whey into value-added foods. In this scenario, advantages could derive from the involvement of SMEs that belong to the same PDO cheese consortium, in terms of standardization of whey, third party certification and possible use of smart traceability tools. Hence, the SMEs producing PDO products could advance the application of the bioeconomy principles in the food system. Research challenges to promote the implementation of the conceived whey value chain are finally outlined.
•Efficient whey recycling processes can be performed with large whey inflow (>100 t/d).•High-quality Protected Designation of Origin (PDO) cheeses are made at small/medium enterprises (SMEs).•SMEs could contribute to whey recycling by suppling traceable whey lots to industrial processors.•Smart traceability schemes support a trustable whey value chain involving a multitude of actors.•SMEs processing PDO cheeses could advance the application of the bioeconomy in the food system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The byproduct of cheese-producing industries, cheese whey, is considered as an environmental pollutant due to its high BOD and COD concentrations. The high organic load of whey arises from the ...presence of residual milk nutrients. As demand for milk-derived products is increasing, it leads to increased production of whey, which poses a serious management problem. To overcome this problem, various technological approaches have been employed to convert whey into value-added products. These technological advancements have enhanced whey utilization and about 50% of the total produced whey is now transformed into value-added products such as whey powder, whey protein, whey permeate, bioethanol, biopolymers, hydrogen, methane, electricity bioprotein (single cell protein) and probiotics. Among various value-added products, the transformation of whey into proteinaceous products is attractive and demanding. The main important factor which is attractive for transformation of whey into proteinaceous products is the generally recognized as safe (GRAS) regulatory status of whey. Whey and whey permeate are biotransformed into proteinaceous feed and food-grade bioprotein/single cell protein through fermentation. On the other hand, whey can be directly processed to obtain whey protein concentrate, whey protein isolate, and individual whey proteins. Further, whey proteins are also transformed into bioactive peptides via enzymatic or fermentation processes. The proteinaceous products have applications as functional, nutritional and therapeutic commodities. Whey characteristics, and its transformation processes for proteinaceous products such as bioproteins, functional/nutritional protein and bioactive peptides are covered in this review.
•Cheese whey as a potential resource for various value-added products•Routes of transformation and biotransformation of whey•Bioconversion of whey into yeast bioprotein for feed and food applications•Transformation of whey into functional and nutritional whey proteins•Transformation and biotransformation of whey proteins into bioactive peptides.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In India, annually about 3.3–5 million tons of cheese whey is produced which may causes serious problems for the environment if left untreated. In this study, pretreated cheese whey was utilized to ...produce hydrogen via dark fermentation by Enterobacter aerogenes 2822 cells in 2 L double walled cylindrical bioreactor having working volume of 1.5 L. Effect of change in total carbohydrate concentration in cheese whey (CWTC, 20–45 g L−1), temperature (T, 25–37 °C) and pH (5.5–7.5) was investigated on volumetric hydrogen production rate (VHPR) using Box Behnken design (BBD). Experimental VHPR of 24.7 mL L−1 h−1 was attained at an optimum concentration of 32.5 g L−1 CWTC, 31 °C T and 6.5 pH, which was in good correlation with predicted rate of 23.2 mL L−1 h−1. Mathematical models based on Monod and logistic equations were developed to describe the kinetics of substrate consumption and growth profile of E. aerogenes 2822 under optimum conditions. While for the modelling of fermentative hydrogen production in batch mode, Modified Gompertz equation and Leudeking-Piret models were used which gave proper simulated fitting. These results will add significant values to cheese whey by converting it into a clean form of bioenergy.
•Box Behnken design matrix was used for setting up experimental conditions.•Fermentation experiment in 2 L double walled cylindrical bioreactor.•Response surface analysis was used to depict the results.•Optimum total carbohydrate concentration in cheese whey = 32.5 g L−1, temp. = 31 °C and pH = 6.5.•Experimental and predicted bioH2 production rate were 24.7 mL L−1 h−1 and 23.2 mL L−1 h−1 respectively.•Mathematical models for H2 production gave adequate simulation with experimental values.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The utilization of whey has become a challenge with the significant growth in the production of cheese and coagulated milk products. Consequently, we have developed cost-effective and waste-free ...production technologies for processing whey disposal into a variety of high-quality, value-added food products at the industrial level. This work constitutes a research on the impact of various alcoholic fermentations on functional, structural, and physicochemical properties of fermented whey proteins recovered from whey-based spirit production effluent. The results showed that surface hydrophobicity and sulfhydryl groups of fermented whey protein concentrates (FWPC) increased significantly in comparison with native whey protein concentrate, while the zeta-potential and particle size of non-supplemented FWPC and low-supplemented FWPC were not substantially affected by fermentation. Furthermore, the outcomes indicated that the non-and low-supplemented whey fermentation led to the improvement in the solubility of FWPCs dispersions, and enhancement in the emulsifying activity and stability of FWPCs. Size exclusion chromatography and SDS-Page results also demonstrated significantly increased β-Lg content in FWPCs, which might be attributed to the reinforcement of the β-Lg intramolecular and noncovalent bonds. The enhancement in functionality was probably due to the partially unfolded whey protein molecules, exposing more hydrophobic amino acid residues, thus making the protein more amphiphilic and capable. Nevertheless, high-yield alcoholic fermentation led to critical changes in the structural properties of whey proteins as evidenced by SEM results. Therefore, our findings suggested that the application of recovering FWPCs after producing premium quality potable whey-based spirit from the presence of non-and low-lactose supplemented whey is fully proposed as an industrially recommended alternative for food-grade protein production.
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•Fermentation process significantly increased general properties of FWPC.•More amphiphilic and capable proteins recovered due to exposed hydrophobic amino acids.•Increased β-Lg content in fermented whey protein leads to better functionality.•FWPC is proposed for manufacturing food-grade protein at the industrial level.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Algal wastewater remediation has become attractive for a couple of years now, however the effectiveness of genetic toxicity reducing of some by-products through microalgae are still not well ...reported. This study aimed to evaluate the growth, nutrients and toxicity removal of Chlorella vulgaris cultivated under autotrophic and mixotrophic conditions in three agro-industrial by-products. Mixotrophic culture using corn steep liquor showed higher cell concentration, specific growth rate, maximum cell productivity and biomass protein content when compared to cheese whey and vinasse. Nutrient removal results showed that C. vulgaris was able to completely remove corn steep liquor nutrients, while in cheese whey and vinasse culture this removal was not as efficient, observing remaining COD. This work evaluated for the first time the corn steep liquor and cheese whey genetic toxicity through Allium cepa seeds assay. These results demonstrate that corn steep liquor toxicity was totally eliminated by C. vulgaris cultivation, and cheese whey and vinasse toxicity were minimized. This study proves that the mixotrophic cultivation of C. vulgaris can increase cellular productivity, as well as it is a suitable and economic alternative to remove the toxicity from agroindustrial by-products.
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•Toxicity of corn steep liquor and cheese whey was reported for the first time.•Corn steep liquor toxic power was totally eliminated after microalgae treatment.•Total phosphorus was completely removed in all treated groups.•C. vulgaris is a great alternative for agroindustrial by-products biotreatment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In Friuli-Venezia Giulia plain (North-East of Italy), a significant number of small diaries is present; this study was aimed at evaluating technical and economic feasibility of diffused anaerobic ...digestion implementation at dairy level. Different kinds of cheese whey were characterized, and biochemical methane potential tests were executed. Good methane yields (up to 437.3 NmL CH4/g VSadded) were obtained, applying an inoculum-to-substrate ratio of 6. Ultrasound pre-treatment was investigated to evaluate an eventual increase in methane production and kinetics, varying applied ultrasonic energy: significant increases in methane yield (maximum +16.0%) and CH4 production kinetics (up to +46% increase after 3 days) were obtained at low ultrasonic energy of 251.4–693.7 Wh/kg VS, while at higher ultrasonic energy of 502.8–1387.5 Wh/kg VS no significant effect was visible. Energy consumption in selected dairies was analysed, to underline the impact of anaerobic digestion implementation on electric and thermal energy need, and it was concluded that through cheese whey anaerobic digestion it is possible to cover most of the dairies energy demand. Specific electric and thermal energy consumption were evaluated to be respectively in the range of 0.009–0.133 kWh/kg milk and 0.247–0.557 MJ/kg milk, while specific energy costs were calculated as 0.0079–0.0308 €/kg milk. For each analysed plant, digester volume to install and organic loading rate were hypothesized.
•Cheese whey valorisation through anaerobic digestion is studied.•Biochemical methane potential was in the range of 352.8–437.3 NmL CH4/g VSadded.•A moderate increase in methane yield (+16%) was obtained after ultrasound treatment.•A non-linear correlation was observed between ultrasound energy and methane yield.•Small dairies could implement anaerobic digestion to get most of the needed energy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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