Waste Glycerol Research Articles

Microbial consortia-derived cellulose biomaterial: Synthesis, characterization, and utility in neural tissue regeneration.

Therapeutic application of bacterial cellulose, a polymer produced by fermentative growth of bacteria, is often challenged by low yields and absence of high yielding strains. The current study reports the synthesis and characterization of bacterial cellulose from a novel microbial consortium of Weissela confusa, Neobacillus drentensis, and Bacillus sp. isolated from mother of vinegar and identified by 16S rDNA typing. The bacterial cellulose was characterized by Scanning electron microscopy (SEM), Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (X-RD), and thermogravimetric analysis (TGA). Optimization of bacterial cellulose production was carried out using modified Hestrin Schramm (HS) Media (with industrial waste glycerol) to attain a maximum yield of 17.2 g/l after 10 days of incubation. The cytotoxicity evaluation of bacterial cellulose in murine neuroblastoma Neuro 2a cell lines showed 90 % cell viability after 48 h. Bacterial cellulose facilitated cell attachment and three-dimensional growth of N2a cells, as confirmed by the SEM analysis. We propose that the bacterial cellulose produced by this consortium could serve as a scaffold for neural stem cell-based therapeutic applications.

Harnessing Rhamnolipids from Waste Glycerol for Effective Biocontrol of Fungal Pathogens in Cucumber and Melon Plants

Effective postharvest management is essential to maintaining the quality and safety of fruits and vegetables, particularly in preventing decay caused by fungal pathogens. This study explored the potential of rhamnolipids (RLs), a biofungicide derived from waste glycerol, to control fungal infections and enhance the postharvest quality of tomatoes, cucumbers, and mangoes. Initial experiments identified pathogenic fungi impacting these fruits, with Botrytis cinerea, Colletotrichum capsici, and Phytophthora palmivora showing the highest virulence in tomatoes, cucumbers, and mangoes, respectively. However, the primary focus was on evaluating RLs' efficacy in mitigating disease severity and reducing postharvest decay, weight loss, and total soluble solids (TSS) content. RL-treated fruits demonstrated significant improvements in postharvest quality: by day six, RL treatment reduced decay and weight loss in all fruits compared to untreated controls, with RL-treated tomatoes, cucumbers, and mangoes showing decay levels of 22.63%, 15.98%, and 50% respectively, alongside controlled weight loss. Interestingly, RL-treated cucumbers also exhibited an increase in TSS (3.4) even under pathogen pressure, suggesting enhanced sugar content and improved quality. Overall, these findings highlight RLs as a promising biocontrol agent, capable of managing fungal infections while preserving fruit quality during storage. This work underscores the potential of RLs in developing sustainable postharvest interventions against fungal pathogens.

Efficacy of Rhamnolipids in Mitigating Postharvest Fungal Infections and Preserving Quality of Tomatoes, Cucumbers, and Mangoes

Effective postharvest management is essential to maintaining the quality and safety of fruits and vegetables, particularly in preventing decay caused by fungal pathogens. This study explored the potential of rhamnolipids (RLs), a biofungicide derived from waste glycerol, to control fungal infections and enhance the postharvest quality of tomatoes, cucumbers, and mangoes. Initial experiments identified pathogenic fungi impacting these fruits, with Botrytis cinerea, Colletotrichum capsici, and Phytophthora palmivora showing the highest virulence in tomatoes, cucumbers, and mangoes, respectively. However, the primary focus was on evaluating RLs' efficacy in mitigating disease severity and reducing postharvest decay, weight loss, and total soluble solids (TSS) content. RL-treated fruits demonstrated significant improvements in postharvest quality: by day six, RL treatment reduced decay and weight loss in all fruits compared to untreated controls, with RL-treated tomatoes, cucumbers, and mangoes showing decay levels of 22.63%, 15.98%, and 50% respectively, alongside controlled weight loss. Interestingly, RL-treated cucumbers also exhibited an increase in TSS (3.4) even under pathogen pressure, suggesting enhanced sugar content and improved quality. Overall, these findings highlight RLs as a promising biocontrol agent, capable of managing fungal infections while preserving fruit quality during storage. This work underscores the potential of RLs in developing sustainable postharvest interventions against fungal pathogens.

Synergistic impact of co-substrate of biodiesel crude glycerol and durian peel hydrolysate for biohydrogen and 1,3-propanediol synthesis by Clostridium butyricum

Aligning with Sustainable Development Goals 7 and 12, this project explores the utilization of durian peel and waste glycerol as sustainable carbon sources to produce green biohydrogen and 1,3-propanediol. The study elucidates the synergistic impact of the glucose-glycerol co-substrate ratio for the co-production of 1,3-propanediol and biohydrogen. Then, the ratio is applied to durian peel hydrolysate and biodiesel glycerol. A glycerol-to-glucose ratio of 10:1 by mass produces a maximum hydrogen productivity and yield of 67.46 mL/L∙h and 0.11 mol H2/mol substrate consumed and a fairly high 1,3-propanediol titer, yield and productivity. Moreover, the application of waste-derived carbon sources, i.e., durian peel hydrolysate and treated glycerol, enhances H2 yield and productivity by 18.9% and 7.5%, respectively. These findings promote biofuel and bioplastic application, establishing a flagship circular bioeconomy technology in the ASEAN region to cater to regional polyester, resin and energy demand while promoting waste reduction and lower greenhouse gas emissions.

Scaled-up production and recovery of lipopeptide biosurfactant and its application for washing petroleum-contaminated drill cuttings

A simple and efficient fermentation strategy using chitosan-immobilized Bacillus subtilis GY19 was developed for large-scale lipopeptide production from waste glycerol and palm oil. When a fed-batch fermentation approach was employed, excessive foaming was minimized, while lipopeptide production was greater than that of conventional batch fermentation. When a 700 L stirred tank fermenter with a 400 L working volume was used, a lipopeptide concentration and yield of 7.55 g/L and 0.190 g/g of substrate, respectively, were achieved. The pilot-scale recovery process involved sequential bacterial cell removal via centrifugation, elimination of impurities through acidification of the cell-free broth, and partial purification and concentration of the lipopeptides via ultrafiltration. A 5 kDa stabilized cellulose-based membrane maintained a constant permeate flux and resulted in 67.2 % lipopeptide recovery. The concentrated lipopeptide retentate contained 16.8 g/L lipopeptides and a surface tension of 28.82 mN/m. A biobased washing agent for the treatment of petroleum-contaminated drill cuttings was later formulated with the retentate and various vegetable oil-based surfactants via the simplex−lattice mixture design methodology. The mixture of 1 % retentate and 4 % fatty alcohol ethoxylate 5EO presented the greatest removal efficiency of 83.2 % for drill cuttings containing 15 % (w/w) total petroleum hydrocarbons. The formulation also mobilized petroleum hydrocarbons into a distinct free oil layer, which would be easy to separate and subsequently recycle. These findings demonstrate the scalability of the lipopeptide production and recovery process, while the biobased washing agent offers an environmentally friendly approach for petroleum remediation.

Production of Lactic Acid via Catalytic Transfer Dehydrogenation of Glycerol Catalyzed by Base Metal Salt Ferrous Chloride and Its NNN Pincer-Iron Complexes.

NNN-Bis(imino) pyridine-based pincer-Fe(II) complexes with an expected trigonal bipyramidal (TBP) geometry equilibrated to a rearranged ion pair of an octahedral dicationic Fe complex containing two bis(imino)pyridine ligands that are neutralized by a tetrahedral dianionic-[FeCl4]2-. Single-crystal X-ray diffraction (SCXRD), high-resolution mass spectrometry (HRMS), and UV-visible (UV-vis) studies suggested that the equilibrium was dictated by the sterics of the R group on the imine N, with the less-crowded groups tilting the equilibrium to the ion pair and the bulky ones favoring the TBP geometry. Electron paramagnetic resonance (EPR) and Evan's magnetic moment measurements indicated that the complexes were paramagnetic with Fe(II) in a high-spin state. In solution, over a period of 7 days, these Fe(II) complexes oxidized to a mixture of low-spin and high-spin Fe(III) species. These pincer-Fe(II) were found to be highly active toward the transformation of biodiesel waste glycerol to value-added lactic acid (LA). Particularly, (Ph2NNN)FeCl2 (0.1 mol %) gave 91% LA with a 99% selectivity at 140 °C using 1.2 equiv of NaOH. With 0.0001 mol % (Ph2NNN)FeCl2, very high turnovers (74% LA, 98% selectivity, 740 000 turnover number (TON) at 4405 turnovers per hour (TOs/h)) were obtained after 7 days. EPR indicated Fe(III) species to be the active catalyst, a few of which were detected by HRMS. Experiments with Hg are suggestive of the mostly homogeneous molecular nature of the catalyst with a minor contribution from heterogeneous Fe nanoparticles.

Catalytic Cascade for Biomass Valorisation: Coupled Hydrogen Transfer Initiated Dehydration and Self-Aldol Condensation for the Synthesis of 2-methyl-pent-2-enal from 1,3-propanediol

A one-pot, one-step protocol combining hydrogen transfer initiated dehydration (HTID) of 1,3-propanediol (1,3-PDO), catalysed by [Cp*IrCl2(NHC)] (Cp* = pentamethylcyclopentadienyl; NHC = carbene ligand) complexes (1-5H and 1-3F), and self-aldol condensation (SAC) of propanal (2), allowed selective production of C6 aldehyde 2-methyl-pent-2-enal (3), in ionic liquids with high substrate conversion. This shows, for the first time, the conversion of 1,3-propanediol to C6 aldehydes in one pot via a catalytic hydrogen borrowing methodology. The Ir(III) pre-catalysts and the ionic liquids were recyclable. C6 aldehyde 2-methyl-pent-2-enal could also be selectively produced in the presence of water and in neat 1,3-PDO. The efficient, selective delivery of a value-added chemical from 1,3-PDO, a major product of many whole-cell bacterial fermentation processes, shows that the combination of chemo-catalytic processing of the chemical platform via Cp*IrCl2(NHC)-catalysed HTID/SAC with bio-catalysis has the potential to allow direct valorisation of the bio-renewable feedstocks, such as waste glycerol and sugars, into valuable chemicals.

Metabolic versatility of anaerobic sludge towards platform chemical production from waste glycerol

Waste glycerol is produced in excess by several industries, such as during biodiesel production. In this work, the metabolic versatility of anaerobic sludge was explored towards waste glycerol valorization. By applying different environmental (methanogenic and sulfate-reducing) conditions, three distinct microbial cultures were obtained from the same inoculum (anaerobic granular sludge), with high microbial specialization, within three different phyla (Thermodesulfobacteriota, Euryarchaeota and Pseudomonadota). The cultures are capable of glycerol conversion through different pathways: (i) glycerol conversion to methane by a bacterium closely related to Solidesulfovibrio alcoholivorans (99.8% 16S rRNA gene identity), in syntrophic relationship with Methanofollis liminatans (98.8% identity), (ii) fermentation to propionate by Propionivibrio pelophilus strain asp66 (98.6% identity), with a propionate yield of 0.88 mmol mmol−1 (0.71 mg mg−1) and a propionate purity of 80–97% and (iii) acetate production coupled to sulfate reduction by Desulfolutivibrio sulfoxidireducens (98.3% identity). In conclusion, starting from the same inoculum, we could drive the metabolic and functional potential of the microbiota towards the formation of several valuable products that can be used in industrial applications or as energy carriers.Key pointsVersatility of anaerobic cultures was explored for waste glycerol valorizationDifferent environmental conditions lead to metabolic specializationBiocommodities such as propionate, acetate and methane were produced

The Biosynthesis of Liquid Fuels and Other Value-Added Products Based on Waste Glycerol—A Comprehensive Review and Bibliometric Analysis

The Biosynthesis of Liquid Fuels and Other Value-Added Products Based on Waste Glycerol—A Comprehensive Review and Bibliometric Analysis

Metabolic Engineering of Bacillus subtilis for the Production of Poly-γ-Glutamic Acid from Glycerol Feedstock

Poly-γ-glutamic acid (γ-PGA) is an attractive biopolymer for medical, agri-food, and environmental applications. Although microbial synthesis by Bacilli fed on waste streams has been widely adopted, the obtainment of efficient sustainable production processes is still under investigation by bioprocess and metabolic engineering approaches. The abundant glycerol-rich waste generated in the biodiesel industry can be used as a carbon source for γ-PGA production. Here, we studied fermentation performance in different engineered Bacillus subtilis strains in glycerol-based media, considering a swrA+ degU32Hy mutant as the initial producer strain and glucose-based media for comparison. Modifications included engineering the biosynthetic pgs operon regulation (replacing its native promoter with Physpank), precursor accumulation (sucCD or odhAB deletion), and enhanced glutamate racemization (racE overexpression), predicted as crucial reactions by genome-scale model simulations. All interventions increased productivity in glucose-based media, with Physpank-pgs ∆sucCD showing the highest γ-PGA titer (52 g/L). Weaker effects were observed in glycerol-based media: ∆sucCD and Physpank-pgs led to slight improvements under low- and high-glutamate conditions, respectively, reaching ~22 g/L γ-PGA (26% increase). No performance decrease was detected by replacing pure glycerol with crude glycerol waste from a biodiesel plant, and by a 30-fold scale-up. These results may be relevant for improving industrial γ-PGA production efficiency and process sustainability using waste feedstock. The performance differences observed between glucose and glycerol media also motivate additional computational and experimental studies to design metabolically optimized strains.

Valorization of waste glycerol into value-added dihydroxyacetone via microbial fermentation: feasibility study

The waste glycerol generated during biodiesel production can be converted into a value-added product like dihydroxyacetone (DHA). DHA is widely applied in the cosmetic industry as a color additive in sunless tanning products. There is a market demand for DHA as the revenue for sunless tanning products is growing. Study on reviewing the viability of an industry-scaled DHA production plant is scarce. Therefore, it is the aim of this study to examine and evaluate the feasibility of the DHA production plant in terms of technical, economical, and safety aspects. In this present study, the DHA is synthesized from glycerol via microbial fermentation using Gluconobacter oxydans. The production process is designed and simulated using Aspen Plus software. Preliminary process hazards and safety reviews are conducted using HAZOP and process material risk assessment. Techno-economic and sensitivity analyses are also performed. The simulation results indicate that with 6266 tons of crude glycerol, 3871 tons of DHA can be generated annually. The DHA production from crude glycerol is found to be technically and economically viable. The DHA plant is able to retain profitability at ± 25% fluctuation of the DHA selling price, with a payback period of less than 5 years. The findings from this work provide insight into the feasibility of the valorization of waste crude glycerol from biodiesel synthesis into DHA.Graphical abstract

Harnessing waste glycerol to mitigate salinity constraints in freshwater microalgae cultivation for enhanced biodiesel recovery

The current study investigated the synergistic effect of waste glycerol and salinity on Scenedesmus obliquus cultivation for enhanced biomass and biodiesel production. Optimal glycerol concentration was identified at 0.08 M supplementation, resulting in 23.1 % significant increase in biomass productivity. However, higher glycerol concentrations resulted in growth retardation. Salinity of +200 % NaCl showed positive impact on the growth, with the highest recorded dry weight of 1.76 g/L and biomass productivity of 0.206 g/L.day. However, further increases in salinity resulted in 53.4 % reduction in biomass yield at +800 % NaCl compared to +200 % NaCl. The combined treatment of the optimum glycerol concentration at different salinities (Glyc + Salin) showed superior growth performance up to +600 % NaCl, which confirmed mitigation of salinity inhibitory effects. Glyc + Salin exhibited the highest recorded nitrogen and phosphorus removal efficiencies (98.1 % and 96.6 %, respectively at day 8), dry weight (2.02 g/L), and biomass productivity (0.231 g/L.day). Notably, lipid content increased to 240.4 mg/g dw, and lipid productivity reached 56.0 mg/L.day, representing 76.1 % improvement over the control. Biodiesel characteristics, including cetane numbers and iodine values, showed also improvement, confirming the potential of Glyc + Salin for sustainable microalgal cultivation and biodiesel production.

Biogas and Biohythane Production from Anaerobic Co-digestion of Canned Sardine Wastewater with Glycerol Waste

A biochemical methane potential (BMP) test investigated the effect of glycerol waste (GW) concentration on anaerobic co-digestion with canned sardine wastewater (CSW). They were studied using the single-stage process at mesophilic (P1) and thermophilic (P2) conditions and two-stage mesophilic (P3) processes. The P3 process has provided the most significant potential for improving biogas production in the sardine canning industry. Using 4% GW (v/v), the optimal hydrogen and methane concentrations at P3 are 43.00 ml H2/g CODr and 303.69 ml CH4/g CODr, respectively. The P3 process was 11.33 m3 biohytane/m3 mixed substrate, and the biohytane composition contained 43.11% CH4, 21.45% H2, and 35.43% CO2. The modified Gompertz model could simulate satisfactory hydrogen and methane yields, corresponding to high regression coefficients (R2>0.90). Hydrogen-producing bacteria in the H2 batch reactor were dominated by Micrococcus sp. and Desulfovibrio sp., while Methanosaeta sp., Methanoculleus sp., and Methanosarcina sp. are the major methanogens in the CH4 batch reactor. A two-stage process of co-fermenting CSW and GW could be a potential option for simultaneous biofuel recovery and waste treatment.

Batch Fermentation of Salt-Acclimatizing Microalga for Omega-3 Docosahexaenoic Acid Production Using Biodiesel-Derived Crude Glycerol Waste as a Low-Cost Substrate

Biodiesel produced from waste cooking oil (WCO) is on the rise and inevitably leads to issues in managing glycerol waste. Due to the presence of colour, odour and other minor compounds, the refining costs for this type of glycerol are higher and uneconomical. The potential of biodiesel-derived glycerol waste (BDGW) obtained from WCO to produce the highly added product of docosahexaenoic acid (DHA), also known as omega-3 polyunsaturated fatty acid, via the marine microalga of Schizochytrium limacinum ATCC MYA-1381 under aerobic batch fermentation was investigated. Cell growth, as well as DHA production, were performed under various operating conditions, including aeration rates and BDGW concentrations. The effect of the substrate type on cell growth and DHA yield was evaluated. The optimum operating condition was obtained when the air flow of a 0.25 vvm and 50 g/L of the glycerol concentration was fed into the fermenter and maximum cell dry weight (11.40 g/L) and DHA yield (665.52 mg/g) were achieved. However, cell growth and DHA yield were not significantly different when S. limacinum was grown using various carbon sources. Successfully, it clearly demonstrates that the BDGW can be used as a cheap carbon source for DHA production via marine microalgae using aerobic batch fermentation.

Biodiesel-Derived Waste Glycerol as a Green Template for Creating Mesopores in the ZSM-5 Catalyst for Aromatics Production Applications.

The present study provides a novel sustainable approach for the synthesis of the ZSM-5 catalyst using biodiesel-derived waste glycerol as a green template as well as a mesopore creator, which is here reported for the first time, to the best of our knowledge. The use of bioglycerol in the preparation of ZSM-5 (Zn-Z-G and Zn-Z-T) materials exhibited a typical MFI zeolite structure, indicating glycerol played a similar role to that of a typical (TPA+) template in the formation of the ZSM-5 zeolite structure. The Zn-Z-G material also exhibited a large mesopore in the ZSM-5 pore structure, suggesting that glycerol played both template and mesopore creator roles. Interestingly, Zn-Z-GT prepared by the dual-template route using bioglycerol along with typical TPA+ showed a MFI zeolite structure with special catalytic features such as hierarchical micromesopores and well-balanced acid sites. These results reveal that the use of bioglycerol along with a typical TPA+ template had a promotional effect on creating such special properties in the Zn-Z-GT material. The Zn-Z-GT catalyst exhibited excellent catalytic performance in the naphtha aromatization reaction, resulting in achieving ∼58 wt % of the aromatic product and useful gas byproduct (14 wt %) with a minimum coke content (∼4 wt %) in a 12 h reaction period ascribed to its combined effect of hierarchical micromesopores and well-balanced acidity with optimum Lewis acid sites. The liquid product possessing high alkyl-aromatics with a high octane value (RON ∼ 109) produced in the present study can be used as an octane booster for liquid gasoline. The high alkyl-aromatics (>50 wt %) content of the liquid product also attracts various petrochemical applications. The effective utilization of waste bioglycerol as a green template and mesopore creator for the preparation of Zn-Z-GT can exhibit sustainability in the resultant material.

Mixed culture resource recovery from industrial waste glycerin pitch: Microbial analysis and production of bio-flocculants extracellular polymeric substances

Conventional glycerin pitch (GP) waste management strategies exacerbate environmental pollution. Resource recovery from GP has been demonstrated using chemical methods and fermentation using pure cultures, but the use of mixed cultures remains undetermined. Thus, our previous study investigated the potential of mixed cultures resource recovery from GP where we have successfully cultivated microorganisms from activated sludge to produce extracellular polymeric substances (EPS) and polyhydroxyalkanoates (PHA) from GP. In this study, microbial community of the enriched microorganisms was characterized and the potential of EPS as bio-flocculants was investigated. Cultivation reactor performance and bioinformatic analyses revealed that the aerobic dynamic feeding strategy cultivated EPS producers such as Rhodocyclaceae Thauera (18.62 %), Rhodanobacteraceae Dokdonella (9.26 %) and Phacelicystidaceae Phaselicystis (2.39 %). Batch tests with 1.5 g C/L GP revealed that the enriched microorganisms could remove the organic compounds in GP by 83 % to produce 128 mg EPS/g volatile solids. The EPS extracted displayed optimal kaolin flocculation activities of 100 % at 2.5 mL dosage and pH 7 using 1 % (w/v) calcium chloride. The EPS were also reported to have optimal flocculation activities of 71 % and 100 % with real oleochemical wastewater, WW1 and WW2, respectively at 7.0 mL dosages and pH 7 using 8 % (w/v) calcium chloride. The study proposes using mixed cultures to convert GP into EPS for use as bio-flocculants, which would introduce a circular economy concept in the oleochemical industry.

Enhanced Efficiency for Biogas Production from Distillery Wastewater as Mixed with Molasses and Glycerol Waste in the Anaerobic Co-Digestion

This experiment was conducted to decide the impact of molasses and glycerol waste on upgraded methane production in anaerobicco-digestion with distillery wastewater. Co-substrates used for biogas production in the anaerobic co-fermentation process ofdistillery wastewater (DW) were molasses (ML) and glycerol waste (GW). The co-substrate concentration in all batch experimentsvaried between 1% and 5% (v/v). To study the efficiency of biogas production, the optimal ratio was chosen for operation in thePFR continuous reactor. Optimization results indicated that anaerobic co-digestion of DW with 5% GW and 1% ML could improvebiogas quality and quantity. HRT for 30 days allowed R2 (95% DW: 5% GW) to produce maximum methane production per 11 m3CH4/m3mixed wastewater, followed by R1 (99% DW: 1%). ML) 6 m3CH4/m3mixed wastewater and control (100% DW) could onlyproduce 2.7 m3CH4/m3mixed wastewater methane. As co-substrates, GW and ML can be balanced to coordinate the C/N ratio andpH of DW. In particular, the C/N ratio of the mixed sewage can be balanced, and the concentration of ammonia nitrogen within ananaerobic digestion tank can be diluted. Therefore, GW can be used as an optimal co-substrate as it improves the C/N ratio, dilutestoxic compounds within DW, and provides lower prices, thus increasing the potential for methanogenesis within DW affected toincrease biogas production.

Itaconate Production from Crude Substrates with U. maydis: Scale-up of an Industrially Relevant Bioprocess

BackgroundIndustrial by-products accrue in most agricultural or food-related production processes, but additional value chains have already been established for many of them. Crude glycerol has a 60% lower market value than commercial glucose, as large quantities are produced in the biodiesel industry, but its valorisation is still underutilized. Due to its high carbon content and the natural ability of many microorganisms to metabolise it, microbial upcycling is a suitable option for this waste product.ResultsIn this work, the use of crude glycerol for the production of the value-added compound itaconate is demonstrated using the smut fungus Ustilago maydis. Starting with a highly engineered strain, itaconate production from an industrial glycerol waste stream was quickly established on a small scale, and the resulting yields were already competitive with processes using commercial sugars. Adaptive laboratory evolution resulted in an evolved strain with a 72% increased growth rate on glycerol. In the subsequent development and optimisation of a fed-batch process on a 1.5-2 L scale, the use of molasses, a side stream of sugar beet processing, eliminated the need for other expensive media components such as nitrogen or vitamins for biomass growth. The optimised process was scaled up to 150 L, achieving an overall titre of 72 g L− 1, a yield of 0.34 g g− 1, and a productivity of 0.54 g L− 1 h− 1.ConclusionsPilot-scale itaconate production from the complementary waste streams molasses and glycerol has been successfully established. In addition to achieving competitive performance indicators, the proposed dual feedstock strategy offers lower process costs and carbon footprint for the production of bio-based itaconate.

Bioconversion of waste glycerol into viscosinamide by Pseudomonas fluorescens DR54 and its activity evaluation

Lipopeptides, derived from microorganisms, are promising surface-active compounds known as biosurfactants. However, the high production costs of biosurfactants, associated with expensive culture media and purification processes, limit widespread industrial application. To enhance the sustainability of biosurfactant production, researchers have explored cost-effective substrates. In this study, crude glycerol was evaluated as a promising and economical carbon source in viscosinamide production by Pseudomonas fluorescens DR54. Optimization studies using the Box − Behnken design and response surface methodology were performed. Optimal conditions for viscosinamide production including glycerol 70.8 g/L, leucine 2.7 g/L, phosphate 3.7 g/L, and urea 9.3 g/L were identified. Yield of viscosinamide production, performed under optimal conditions, reached 7.18 ± 0.17 g/L. Preliminary characterization of viscosinamide involved the measurement of surface tension. The critical micelle concentration of lipopeptide was determined to be 5 mg/L. Furthermore, the interactions between the viscosinamide and lipase from Candida rugosa (CRL) were investigated by evaluating the impact of viscosinamide on lipase activity and measuring circular dichroism. It was observed that the α-helicity of CRL increases with increasing viscosinamide concentration, while the random coil structure decreases.

Biotechnological Valorization of Waste Glycerol into Gaseous Biofuels—A Review

The supply of waste glycerol is rising steadily, partially due to the increased global production of biodiesel. Global biodiesel production totals about 47.1 billion liters and is a process that involves the co-production of waste glycerol, which accounts for over 12% of total esters produced. Waste glycerol is also generated during bioethanol production and is estimated to account for 10% of the total sugar consumed on average. Therefore, there is a real need to seek new technologies for reusing and neutralizing glycerol waste, as well as refining the existing ones. Biotechnological means of valorizing waste glycerol include converting it into gas biofuels via anaerobic fermentation processes. Glycerol-to-bioenergy conversion can be improved through the implementation of new technologies, the use of carefully selected or genetically modified microbial strains, the improvement of their metabolic efficiency, and the synthesis of new enzymes. The present study aimed to describe the mechanisms of microbial and anaerobic glycerol-to-biogas valorization processes (including methane, hydrogen, and biohythane) and assess their efficiency, as well as examine the progress of research and implementation work on the subject and present future avenues of research.