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The production of polyhydroxyalkanoates using submerged cultures of Cupriavidus necator DSM 428 was evaluated using low-cost substrates from agroindustry: (i) dextrose from cassava starch and (ii) a mixture of sugarcane vinasse from the bioethanol industry and dextrose from cassava starch. The effects of vinasse composition (2.5, 5.0, 7.5, 25, 50, and 75% v/v) and the use of raw and activated carbon-pre-treated vinasse were assessed. The results indicate that cultivations using only cassava starch dextrose reached 4.33 g/L of biomass as the dry cell weight and a poly(3-hydroxybutyrate) (PHB) production of 47.1%. Raw vinasse proportions of 25, 50, and 75% in the culture medium resulted in total inhibition. Vinasse treated at the same ratios led to biomass production in the range 1.7–4.44 g/L. The higher PHB production scenario was obtained in a medium containing dextrose and treated vinasse (7.5%), yielding 5.9 g/L of biomass and 51% of PHB accumulation. The produced PHB was characterized by XRD and FTIR for an analysis of crystalline structure and chemical functional groups, respectively. EDS was employed for a semi-quantitative analysis of the chemical composition, and SEM was used to analyze the morphology of the microgranules. The results of DSC and TGA analyses demonstrated the thermal stability of the obtained PHB. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) relies on the cooperation of specific microbial communities, making it susceptible to process disruptions that could impact biogas production. In this regard, this study presents a technological solution based on the Arduino platform, in the form of a simple online monitoring system that can track the produced biogas profile, named as biogas analyzer module (BAM). The applicability of the BAM focused on monitoring the biogas produced from sugarcane vinasse inoculated with sewage sludge biodigestion processed in mesophilic conditions (38 oC), in a pH range of 6.5–7.5, and following a three-stage operational model: (i) an adaptation (168 h), (ii) complete mixing (168 h), and (iii) bio-stimulation with glycerol (192 h). Then, the lab-made BAM was used to trace the produced biogas profile, which registered a total biogas volume of 8,719.86 cm3 and biomethane concentration of 95.79% (vol.), removing 90.8% (vol) of carbon dioxide (CO2) and 65.2% (vol) of hydrogen sulfide (H2S). In conclusion, the results ensured good accuracy and efficiency to the device created by comparisons with established standards (chromatographic and colorimetric methods), as well as the cost reduction. The developed device would likely be six times cheaper than what is available in the market. [ABSTRACT FROM AUTHOR]

The production of polyhydroxyalkanoates using submerged cultures of Cupriavidus necator DSM 428 was evaluated using low-cost substrates from agroindustry: (i) dextrose from cassava starch and (ii) a mixture of sugarcane vinasse from the bioethanol industry and dextrose from cassava starch. The effects of vinasse composition (2.5, 5.0, 7.5, 25, 50, and 75% v/v) and the use of raw and activated carbon-pre-treated vinasse were assessed. The results indicate that cultivations using only cassava starch dextrose reached 4.33 g/L of biomass as the dry cell weight and a poly(3-hydroxybutyrate) (PHB) production of 47.1%. Raw vinasse proportions of 25, 50, and 75% in the culture medium resulted in total inhibition. Vinasse treated at the same ratios led to biomass production in the range 1.7–4.44 g/L. The higher PHB production scenario was obtained in a medium containing dextrose and treated vinasse (7.5%), yielding 5.9 g/L of biomass and 51% of PHB accumulation. The produced PHB was characterized by XRD and FTIR for an analysis of crystalline structure and chemical functional groups, respectively. EDS was employed for a semi-quantitative analysis of the chemical composition, and SEM was used to analyze the morphology of the microgranules. The results of DSC and TGA analyses demonstrated the thermal stability of the obtained PHB.

Anaerobic co-digestion (co-AD) of agro-industrial waste, namely, palm oil mill effluent (POME) and sugarcane vinasse (Vn), with water hyacinth (WH) as co-substrate was carried out in two separate Anaerobic Suspended Growth Closed Bioreactors (ASGCBs) under thermophilic (55 °C) conditions. The highest chemical oxygen demand (COD) and soluble COD reduction in co-AD of POME-WH (78.61%, 78.86%) is slightly higher than co-AD of Vn-WH (75.75%, 78.24%). However, VFA reduction in co-AD of POME-WH (96.41%) is higher compared to co-AD of Vn-WH (85.94%). Subsequently, biogas production peaked at 13438 mL/day values and 16122 mL/day for co-AD of POME-WH and Vn-WH, respectively. However, the methane content was higher in the co-AD of POME-WH (72.04%) than in the co-AD of Vn-WH (69.86%). Growth yield (YG), maximum specific substrate utilization rate (rx,max) and maximum specific biomass growth rate (μmax) are higher in co-AD of POME-WH, as supported by the higher mixed liquor volatile suspended solids (MLVSS) and COD reduction efficiency compared to co-AD of Vn-WH. However, methane yield ( Y CH 4 ) reported in the co-AD of POME-WH and Vn-WH are 0.2748 and 0.3112 L CH4/g CODreduction, respectively, which suggests that WH is a more suitable co-substrate for Vn compared to POME. [ABSTRACT FROM AUTHOR]

Sugarcane vinasse (SV) is the main by-product of bioethanol production. It is considered a potential pollutant due to its acidity index and the presence of organic components, suspended solids and heavy metals. High levels of SV production are undoubtedly a threat to the environment and the community in general. The aim of this study was to evaluate the main SV dispositions or treatments, in addition to their applications, by using bibliometric maps for metadata analysis. It was found that the studies related to SV were focused in (i) anaerobic digestion (AD), (ii) fertirrigation, (iii) coagulation/flocculation, (iv) algae, microalgae and fungi, and (v) biohydrogen production. Additionally, it was determined that the most effective treatment for SV was AD, reaching 90% chemical oxygen demand removal efficiency and energy recovery between 85 and 95% as biogas. Finally, the challenges and opportunities facing Latin America with the growing production of SV were addressed, as well as a detailed review of its treatment and/or disposal, including optimal conditions for the production of value-added products. [ABSTRACT FROM AUTHOR]

• Performance evaluation of a hermophilic anMDBR for sugarcane vinasse treatment. • Overall COD removal efficiencies were above 94% during operation for both effluents. • Ultrafiltered vinasse affected the anMDBR performance by lower COD/SO 4 2- ratios. • The dissociation of VFAs in the mixed liquor hampered their recovery in the distillate. • Low methane contents in the biogas were mainly attributed to H 2 S production. This study presents the first feasibility evaluation of a lab-scale thermophilic anaerobic membrane distillation bioreactor (AnMDBR) for treating sugarcane vinasse, considering the use of waste heat from vinasse which comes from ethanol distillation at high temperatures (80–90 °C). This research focuses mainly on evaluating the VFA production and recovery from anaerobically digested sugarcane vinasse in a single-stage An-MDBR system, alongside monitoring the generation of bioCH4, another bioproduct. The AnMDBR was fed with raw vinasse (phase I) and with ultrafiltered vinasse (phase II). The ultrafiltration of the sugarcane vinasse as pre-treatment stage resulted in a reduction in the COD/SO 4 2- ratio, adversely impacting process performance. The system achieved high removal efficiencies of COD (98 ± 1 % when fed with raw vinasse, and 94 ± 4 % with ultrafiltered vinasse), phosphorus (almost 100 %) and ammonia nitrogen (∼91 %). Regarding byproducts, the system showed low efficiencies in the VFAs recovery in the distillate and low methane content of the biogas formed. To enhance the VFA recovery, the pH of the solution should be kept below the pKa values favoring the VFA transport across the membrane. The permeate flux exhibited a decline throughout operation (from 4.4 to 0.5 L/(m2·h)), attributed to the fouling layer formation. Thus, strategies to mitigate membrane fouling are crucial for improving permeate flux and, consequently, enhancing the feasibility of full-scale MDBR for sugarcane vinasse treatment. [ABSTRACT FROM AUTHOR]

The vinasse is a residue of ethanol production with the potential for methane production, requiring an allochthonous inoculum. Several microorganisms act in the different phases of anaerobic digestion, and the identification of these microbial communities is essential to optimize the process. The characterization of the microbiota involved in the biodigestion of vinasse was observed in the initial stage (IS), at the peak of methane production (MS) and the end of the process (FS) of the best performance assay by high-throughput sequencing. The highest methane production was 0.78 mmolCH4.gVS.h−1 at 243.7 h in the substrate/inoculum ratio of 1.7, with consumption partial of acetic, propionic and isobutyric acids and an 82% reduction of chemical oxygen demand. High microbial diversity was found. The genera Clostridium, Acinetobacter, Candidatus Cloacamonas, Bacteroides, Syntrophomonas, Kosmotoga, the family Porphyromonadaceae and the class Bacteroidia were the most abundant in the maximum methane production. Methane production was driven by Methanobacterium and Methanosaeta, suggesting the metabolic pathways used were hydrogenotrophic and acetoclastic. HIGHLIGHTS The AD of vinasse with allochthonous inoculum reached 82% reduction in COD.; The increase of OLR provided the highest methanogenic activity (0.78 mmol CH4.gVS.h−1).; Clostridium, Candidatus Cloacamonas and Acinetobacter predominated in CH4 production.; Methanobacterium and Methanosaeta drove the methane production.;

There is an emerging interest of use biological processes for vinasse treatment generally because they are able to produce interesting metabolites from living cells. Additionally, the production of yeasts with weakened cell wall without modifying its physiological performance would be of great technological value not only to facilitate the extraction of intracellular metabolites but also to increase the biomass digestibility. This study explored the remediation of a glycerol-fortified sugarcane vinasse using Rhodotorula glutinis or Rhodotorula mucilaginosa coupled with the production of valuable residual biomasses displaying a tailor-made weakened cell wall. Firstly, the biomass-bound ß- d -glucosidase activity was selected as a proper cell wall lytic potential marker. Secondly, in vitro -dose response assays with several metal ions showed that the presence of 6 mM of MnCl 2 and FeCl 3 increased the ß- d -glucosidase activity in R. glutinis and R. mucilaginosa , respectively. Thirdly, the supplementation of those salts to either YPD or vinasse-based media was evaluated. As a result, cells were bigger or even rounder than the corresponding controls (without metal ions supplementation) suggesting a weakening of the cell wall. Finally, as proof of concept, after 6 days of vinasse treatment at 30 °C under stirred conditions, the reduction of COD value for R. glutinis and R. mucilaginosa was 81.3% and 80.8%, respectively. The final biomass, lipid and protein concentrations for R. glutinis were 15.1 g/L, 31.1% and 48.12%, respectively. The final biomass, lipid and protein concentrations for R. mucilaginosa were 15.7 g/L, 31.5% and 48.12%, respectively. Potential technological applications of residual biomass were also discussed. [Display omitted] • Remediation of a glycerol-fortified vinasse by oleaginous yeasts was proposed. • R. glutinis or R. mucilaginosa with a tailor-made weakened cell wall was used. • Treatment of vinasse was coupled with the production of valuable residual biomass. • The reduction of COD value for both biotreatments was about 80%. • Residual biomasses showed a valuable content of lipids (31%) and proteins (48%). [ABSTRACT FROM AUTHOR]

Sugarcane biofuel processing plays an important role in the Brazilian economy, being Brazil the world's largest sugarcane ethanol producer. Nevertheless, the success of its distilleries depends on how they overcome the new scientific challenges faced, mainly regarding the disposal or reuse of sugarcane vinasse. In this sense, the present work uses Aspen Hysys® to simulate an innovative synthesis gas production process integrated into an ethanol distillery. Initially, the distillery is simulated and validated using industrial real data from a plant located in Brazil in order to analyze the potential of sugarcane vinasse generation. Thereafter, conventional (from natural gas) and renewable (from vinasse-based biomass) routes for syngas production through steam methane reforming are compared considering both, technical feasibility and economic investment. Such comparison presents a more rigorous simulation of the vinasse-based plant and shows that the proposed scenario might be 27.87% less expensive than the plant from natural gas. The production plant of syngas from vinasse-based biogas is evaluated to further improve the thermal efficiency and financial performance of the process designed. The results demonstrate that syngas production coupled to ethanol plants is a promising market to countries ascending in technology development for biomass utilization, such as Brazil. [ABSTRACT FROM AUTHOR]

Biodegradable films are a promising strategy to reduce the environmental impact caused by conventional plastics commonly used in agriculture. This study focused on the production and characterization of Konjac glucomannan (KGM) and alginate (ALG) based films enriched with sugarcane vinasse (VIN), a nutrient-rich wastewater generated in large volumes by the sugar-ethanol producing industries. ALG, KGM and ALG/KGM blended (50:50) films were produced by casting and treated with calcium ions (Ca2+) (ALG films) and a combination of Ca2+, alkali, and ethanol (KGM and ALG/KGM films). Vinasse addition tended to reduce transparency and water resistance of the films and had less effect on their mechanical properties. Crosslinking of ALG films resulted in enhanced mechanical properties and reduced moisture content, water solubility, swelling, water vapor permeability, and flexibility. KGM films were less impacted by crosslinking/deacetylation but showed improved water resistance while maintain a high degree of swelling (290% and 185% for KGM and KGM/VIN films respectively). Blended films exhibited characteristic properties of the two biopolymers and adequate compatibility indicated by Fourier transform infrared spectroscopy (FTIR) and morphologies. Vinasse-added ALG/KGM films represent a novel nutrient-enriched, bio-based material for agricultural applications and could help to face the environmental challenges imposed by vinasse disposal. • Konjac glucomannan (KGM)/alginate (ALG) films enriched with vinasse were produced. • Vinasse addition reduced transparency and water resistance of the films. • Crosslinking of ALG films resulted in enhanced mechanical strength and moisture barrier. • KGM based films showed high swelling capacity. • KGM/SA/VIN films are a novel nutrient enriched bio-based material for agricultural applications. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHA) are fully biodegradable biopolymers of microbial origin, with physicochemical characteristics similar to those of conventional synthetic plastics. However, their current production is highly expensive mainly due to the substrate or culture medium employed. In this research, a mixture of cane molasses and residual vinasse from the alcohol industry was evaluated as a substrate using the reference strain Ralstonia eutropha ATCC 17699 to produce PHAs. The results showed the potential of the mixture as a culture medium, after reaching polymer concentrations of 3.17 g/L in MSM medium and 2.71 g/L in M/V medium with a molasses/vinasse ratio of 25/75. There was a sugar (sucrose, fructose, and glucose) consumption yield of 70.7%, and a biopolymer accumulation of 97.8% with respect to the biomass produced. The biopolymer characterization showed a correlation with the standard polyhydroxybutyrate sample - PHB of 99.25%.

Biohydrogen can be produced by dark fermentation of sugarcane vinasse, wastewater from the sugar-alcohol industry, in acidogenic anaerobic bioreactors. In this work, a model based on ADM1 was constructed to model anaerobic processing of sugarcane vinasse in an acidogenic batch reactor. Based on experimental data, hypotheses were put forward. Two new pathways were assumed: A c e t a t e + L a c t a t e → B u t y r a t e + H y d r o g e n and G l y c e r o l → B u t y r a t e + H y d r o g e n. A sensitivity analysis was carried out to reduce the number of free parameters, after which the model was calibrated with the experimental data. The proposed model was able to adequately describe sugar and glycerol consumption, acetate and lactate production and consumption and hydrogen and butyrate production over the operational time at an initial concentration of vinasse of 30 k g C O D m − 3 . Nevertheless more improvements can be carried out to make the model more realistic and to cover intermediate metabolic pathways under conditions of lower vinasse concentration, such as 15 k g C O D m − 3 and 20 k g C O D m − 3 . • An ADM1-based model was constructed to simulate an acidogenic reactor. • Two new metabolic pathways were added to the model. • The number of free parameters was reduced using a sensitivity analysis. • The model suitably described the behavior of substrates and products for 30 kgCODm−3. • Better and constant hydrogen production was observed under 30 kgCODm−3 of vinasse. [ABSTRACT FROM AUTHOR]

This paper reports on a sensitive and selective electrochemical sensor for lactic acid. The sensor is based on molecularly imprinted polymers (MIP), obtained on glassy carbon electrode (GCE) modified with reduced graphene oxide and gold nanoparticles. The MIP was obtained by electropolymerization of the o-phenylenediamine (o-PD) on the modified surface of the GCE in the presence of lactic acid. The steps involving the GCE modification and MIP construction were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy and atomic force microscopy. The results were evaluated using differential pulse voltammetry, using the hexacyanoferrate redox system as an electrochemical probe. Under optimized experimental conditions, the imprinted sensor has a linear response in the 0.1 nM to 1.0 nM lactic acid concentration range, with detection limit of 0.09 nM. The sensor exhibits excellent selectivity in the presence of molecules of similar chemical structure. It was applied for the selective determination of lactic acid in sugarcane vinasse. The recovery values ranged from 97.7 to 104.8%. [ABSTRACT FROM AUTHOR]

Sugarcane cultivation is suitable for the exploitation of organic waste products. However, minimum complementary mineral input is necessary for optimal fertilisation. Control mineral fertilisation treatments with mulch (MCM) or without mulch (MC) were compared with two organic waste treatments, a pig slurry with mulch (PSM) and without mulch (PS), and a sugarcane vinasse with mulch (SVM) and without mulch (SV) on a Nitisol in French Reunion Island. The sugarcane yields obtained with the different treatments differed each year. However, no trend was observed and no significant and recurrent effect of the presence of mulch or of the different treatments was identified over the course of the 4 year experiment. Soil pHw and pH KCl measured in the different treatments increased from year 3 in with the treatments including organic waste products (PS, PSM, SV and SVM) but remained constant with the treatments including only mineral fertilisation (MC and MCM). With the exception of PS and PSM, which were significantly higher in year 4, soil organic carbon content was not modified by the treatments. Soil cation exchange capacity increased only slightly with the PS and PSM treatments from year 3 on. The differences in yields and soil properties can be explained by the nature of the organic waste products, the accumulation of nutrients after several applications, and the specific characteristics of the sugarcane crop. The improvement in soil properties from the third year on was not reflected in the yield of sugarcane because it was too weak, and the crop explores a much larger volume of soil.

This study examines electrochemical post treatment to remove COD, SS, K+ and Cl- from anaerobically treated sugarcane molasses vinasse (ASMV). A platinum coated titanium mesh was used as an electrode material for both the cathode and anode, with 843.18 cm2 of working area. The effects of pH on removal efficiency, as well as energy and electrode consumption, were investigated. Influent ASMV was diluted 10 times and its initial pH was adjusted by addition of HCl and NaOH. The electrolysis experiment was performed at a current density of 94.88 A/m2 with 15 minutes of reaction time, and the effluent was collected after settling for 90 minutes. The results showed that the treatment efficiency was influenced by the initial pH value. A maximal COD removal efficiency (49.25%) was obtained at a pH of 5.0. For SS removal, the maximal efficiency (46.27%) was obtained at a pH of 10.0, and the lowest level of removal occurred at neutral pH conditions. The maximal efficiency of Cl- removal (17.59%) was obtained at a pH of 8.2 (non-adjusted), and its efficiency was lower when influent was adjusted to acidic and neutral pH conditions using HCl. Maximal efficiency of K+ removal (7.23%) occurred at neutral pH conditions and did not occur at alkaline pH values. Energy consumption was lower under pH-adjusted conditions than under non-adjusted conditions, and electrode consumption was higher in both acidic and alkaline conditions relative to neutral pH conditions.

Night biomass loss due to respiratory activity can significantly impact the phytoplankton biomass productivity and the yield of specific biomolecules. A decrease in biomass loss can be achieved by cyclic two-stage cultivation (CTSC) employing an organic carbon source during the dark phase of the photoperiod. Thus, sugarcane vinasse was used as carbon supply in CTSC to influence the Arthrospira maxima growth. The impact of carbon supply on CTSC was assessed and the results show that splitting the supplementation volume of 60 mL supplemented vinasse into three doses of 20 mL during the dark phase increased biomass productivity by 35.4%, although the maximum exponential growth rate was unaffected. The cyanobacterium also takes up CO2 (supplied in the light phase) as HCO3−, high concentrations of which increase biomass loss. Thus, carbon assimilation in CTSC is higher when the concentration of dissolved inorganic carbon is reduced. Optimization of organic and inorganic carbon supply in CTSC with the response surface methodology resulted in an increased growth rate (from 0.73 to 1.18-1.62 day−1) and a reduction of cultivation time (from 7 to 5 days), thus producing a synergistic effect of reduced night biomass loss and vinasse treatment. After cultivating A. maxima for 5 days under optimal conditions (culture medium with 6.81 g L−1 of NaHCO3 and adding 1.5% (v/v) vinasse every 4 h during the dark phase), the reduction of chemical oxygen demand and electrical conductivity demonstrates that removal of organic matter present in the vinasse was due to cell growth during CTSC. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • ADM1 was applied to simulate the anaerobic processing of sugarcane vinasse in AnSBBR. • The biomass concentrations were chosen as free parameters. • ADM1's free parameters were optimized using the Monte Carlo Markov Chain method. • Direct and cross validation elucidate the anaerobic digestion of vinasse at 30 ± 1° C. • The model showed the syntrophism between propionic acid and hydrogendegraders. Abstract The Anaerobic Digestion Model No. 1 (ADM1) was applied in this study to simulate the processing of sugarcane vinasse in an Anaerobic Sequencing Batch Biofilm Reactor (AnSBBR). In the model calibration, the values of the free parameters, concentration of anaerobic biomass for specific species (X su , X c 4 , X pro , X ac , X h 2) 1 1 X su : Sugar degraders, X c 4 : Butyric and valeric acids degraders, X pro : Propionic acid degraders, X ac : Acetic acid degraders, X h 2 : Hydrogen degraders , were obtained by minimizing the objective function expressed by the determinant of the Box-Draper Matrix. Afterwards, these parameters were optimized with the Monte Carlo Markov Chain Method, using the Delayed Rejection Adaptive Metropolis Algorithm. The Geweke statistic test evaluated the convergence of the method. All results passed for direct and cross validation to elucidate the methane production, production and consumption of the organic acids and organic matter removal. The ADM1 was able to show the syntrophism between the species and to describe the experimental data, thus making it possible to be applied in others scenarios. However, it was not so adequate for all conditions in cross validation due to a lack of experimental data and the need to include other metabolic pathways in the model. The chosen concentration of anaerobic biomass for specific species were shown as an important step in this work, because these parameters are difficult to be determined in practice. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHA) are fully biodegradable biopolymers of microbial origin, with physicochemical characteristics similar to those of conventional synthetic plastics. However, their current production is highly expensive mainly due to the substrate or culture medium employed. In this research, a mixture of cane molasses and residual vinasse from the alcohol industry was evaluated as a substrate using the reference strain Ralstonia eutropha ATCC 17699 to produce PHAs. The results showed the potential of the mixture as a culture medium, after reaching polymer concentrations of 3.17 g/L in MSM medium and 2.71 g/L in M/V medium with a molasses/vinasse ratio of 25/75. There was a sugar (sucrose, fructose, and glucose) consumption yield of 70.7%, and a biopolymer accumulation of 97.8% with respect to the biomass produced. The biopolymer characterization showed a correlation with the standard polyhydroxybutyrate sample - PHB of 99.25%. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Vinasse is the main residue from bioethanol production. If discharged in water bodies, it can impair the photosynthetic process causing great damage to the environment. However, this wastewater could be considered a by-product and used as a substrate for obtaining value-added products. In the present work, two basidiomycetous fungi were selected based on their ability to decolorize vinasse and to synthesize lignocellulolytic enzymes in agar medium. Selected fungi were identified as Pycnoporus sp. P6 and Trametes sp. T3. In liquid cultures, both fungi demonstrated their capacity to decolorize and remove phenolic compounds from diluted vinasse, with the concomitant production of ligninolytic enzymes, mainly laccases, suggesting the participation of this enzyme in the bioremediation process. This study proposes that Pycnoporus sp. P6 and Trametes sp. T3 could be used in the design of cutting-edge sustainable biotechnological processes to remedy vinasse, simultaneously synthesizing oxidative enzymes, in an environmentally friendly way. [ABSTRACT FROM AUTHOR]

The fluctuation in the price of oil and the positive consequences of fuels from renewable sources (compared to fossil fuels) propel the expansion of biofuel global production. In this work, the current distillation operation of an ethanol distillery is simulated and compared to the use of indirect heating, evaluating the environmental and economic impacts associated with vinasse fertirrigation by using an external automated tool. Results show that the replacement proposed decreases approximately 15% of the amount of vinasse. Moreover, as the modifications do not change the outlet flowrates, such revamping might be done without additional operational changes that could affect the productivity. The environmental evaluation presents positive results, showing that the new configuration may decrease all environmental impacts categories assessed. From an economic perspective, the plant could also have higher profits, presenting a payback period of 3.57 years. Finally, the new improved system is treated as a multi-objective optimization problem and it is solved by using the weighted sum method to obtain the Pareto frontier, providing the optimal solutions that trade-off economic and environmental objectives. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate in a clear procedure the application of the Anaerobic Digestion Model No. 1 (ADM1) to model a large-scale covered in-ground anaerobic reactor (Cigar), processing sugarcane vinasse from a biorefinery in Brazil. The biochemical make-up (carbohydrates, proteins, and lipids) of the substrate was analysed based on the food industry standards. Two distinct subsets of data, based on the sugarcane harvest season for bioethanol and sugar production in 2012 and 2014, were used to direct and cross validate the model, respectively. We fitted measured data by estimating two key parameters against biogas flow rate: the degradation extent ( fd) and the first order hydrolysis rate coefficient (khyd). By cross validation we show that the fitted model can be generalised to represent the behaviour of the reactor under study. Therefore, motivated by practical and industrial application of ADM1, for both different reactors types and substrates, we show aspects on the implementation of ADM1 to a specific large-scale reactor for anaerobic digestion of sugarcane vinasse. [ABSTRACT FROM AUTHOR]

In this work asymmetric tubular membranes were successfully prepared by the co-use of the slip casting and dip-coating techniques. These membranes were used for treating a sugarcane vinasse sample obtained in ethanol production. This study is supported by a series of experimental tests, including scanning electron microscopy, mercury intrusion porosimetry, and Archimedes tests. Parameters such as color, turbidity and chemical oxygen demand (COD) of vinasse were taken into consideration for evaluating the performance of the membranes prepared herein. On one hand, it was observed that a slip-cast support prepared in this study exhibited an expressive capacity for separating the solid particles present in vinasse from water. On the other hand, the deposition of a boehmite coating on this sample led to a further increase in the membrane performance. Reductions as high as 31, 98 and 89% for COD, turbidity and color were obtained when vinasse was permeated through an asymmetric membrane prepared in this study. [ABSTRACT FROM AUTHOR]

This study aimed to better understand the role of different microbial groups and the determining fermentation pathways in a biohydrogen (bioH 2 )-producing reactor fed with sugarcane vinasse by using next-generation sequencing and principal component analysis (PCA). Both microbial structure and dynamics were characterized. The highest bioH 2 production levels were associated with the Thermoanaerobacterium genus, whilst lactate-producing bacteria comprised the dominant genera (e.g. Lactobacillus and Leuconostoc ) within the reactor at both stable and unstable bioH 2 -producing periods. PCA further revealed that the fermentation of lactate played a dual role in the reactor, as both bioH 2 -producing (acetate + lactate → butyrate + bioH 2 ) and non-bioH 2 -producing (lactate → propionate + acetate) routes could be observed. Overall, the results suggested that lactate is the primary alternative carbon source in vinasse-fed systems subjected to carbohydrate-shortage conditions. [ABSTRACT FROM AUTHOR]

This research investigated the effect of hydraulic retention time (HRT) on two-stage anaerobic membrane bioreactor (2-SAnMBR) performance treating sugarcane vinasse. The experimental setup consisted of an upflow acidogenic reactor and a continuous stirred methanogenic reactor, fitted with submersed microfiltration hollow-fiber membranes. The results indicated excellent performance and robustness of 2-SAnMBR. The reduction in HRT of 5.3–3.1 days did not cause loss of its performance. The 2-SAnMBR showed high capacity of removing organic matter (97%), producing biogas (6.3 Nm 3 of CH 4 per m 3 of treated vinasse) and did not completely remove important nutrients to fertigation. Reducing the HRT, the average mass of soluble microbial products (SMP) and extracellular polymeric substances (EPS) per mass of mixed liquor volatile suspended solids (MLVSS) increased. Consequently, the transmembrane pressure (TPM) rate and fouling resistance rise. Despite the fouling effect, physical and chemical cleaning processes were able to recover operational permeability. [ABSTRACT FROM AUTHOR]

This review aims to present an innovative concept of high value added lipids produced by heterotrophic microorganisms, bacteria and fungi, using carbon sources, such as sugars, acids and alcohols that could come from sugarcane vinasse, which is the main byproduct from ethanol production that is released in the distillation step. Vinasse is a rich carbon source and low-cost feedstock produced in large amounts from ethanol production. In 2019, the Brazilian Ministry of Agriculture, Livestock and Food Supply estimates that growth of ethanol domestic consumption will be 58.8 billion liters, more than double the amount in 2008. This represents the annual production of more than 588 billion liters of vinasse, which is currently used as a fertilizer in the sugarcane crop, due to its high concentration of minerals, mainly potassium. However, studies indicate some disadvantages such as the generation of Greenhouse Gas emission during vinasse distribution in the crop, as well as the possibility of contaminating the groundwater and soil. Therefore, the development of programs for sustainable use of vinasse is a priority. One profitable alternative is the fermentation of vinasse, followed by an anaerobic digester, in order to obtain biomaterials such as lipids, other byproducts, and methane. Promising high value added lipids, for instance carotenoids and polyunsaturated fatty acids (PUFAS), with a predicted market of millions of US$, could be produced using vinasse as carbon source, to guide an innovative concept for sustainable production. Example of lipids obtained from the fermentation of compounds present in vinasse are vitamin D, which comes from yeast sucrose fermentation and Omega 3, which can be obtained by bacteria and fungi fermentation. Additionally, several other compounds present in vinasse can be used for this purpose, including sucrose, ethanol, lactate, pyruvate, acetate and other carbon sources. Finally, this paper illustrates the potential market and microbial processes, using microorganisms, for lipid production. [ABSTRACT FROM AUTHOR]

An experiment on Fenton degradation of sugarcane vinasse was carried out to determine its effect on the wastewater characteristics. Vinasse, a by-product of distillation in the bioethanol industry, contains high organic matter, as the value of chemical oxygen demand (COD) is >100,000 mg/L and BOD5 is 31,250 mg/L. The Fenton reaction is one of the advanced oxidation process (AOP) methods which has been widely applied for the treatment of wastewater containing organic pollutants and contaminants. This method utilizes hydroxyl radical (•OH) produced from the catalyzing reaction between Fe2+ or Fe3+ and hydrogen peroxide. The effect of pH, the ratio of [H2O2] and [COD], and the ratio of [H2O2] to [Fe3+] were studied in this research to evaluate the Fenton reaction. Results from this experiment showed that treatment of vinasse using the Fenton reaction decreased the COD value to 48.10%, and its biodegradability enhanced almost two times at a pH value of 3.8, a ratio of [H2O2] to [COD] of 0.62, and a ratio of [H2O2] to [Fe3+] of 50 (g/g), which demonstrated that the Fenton treatment was effective to reduce organic matter of sugarcane vinasse. Three kinetic models (first order, second order, and Behnajad−Modirshahla−Ghanbery (BMG) kinetic model) were used to evaluate the degradation of the COD value. On the basis of the value of R2 (coefficient of determination), we suggested that BMG represented the best kinetic model. This study finds that the Fenton treatment is able to mitigate the environmental impacts of sugarcane vinasse.

The objective of this study was to investigate the effects of hydraulic retention time (HRT) (8 to 0.5 h) and temperature (55 to 75 °C) in two anaerobic fluidized bed reactors (AFBR) using cheese whey (AFBR-CW = 10,000 mg sugars L) and vinasse (AFBR-V = 10,000 mg COD L) as substrates. Decreasing the HRT to 0.5 h increased the hydrogen production rates in both reactors, with maximum values of 5.36 ± 0.81 L H h L in AFBR-CW and 0.71 ± 0.16 L H h L in AFBR-V. The optimal conditions for hydrogen production were the HRT of 4 h and temperature of 65 °C in AFBR-CW, observing maximum hydrogen yield (HY) of 5.51 ± 0.37 mmol H g COD. Still, the maximum HY in AFBR-V was 1.64 ± 0.22 mmol H g COD at 4 h and 55 °C. However, increasing the temperature to 75 °C reduced the hydrogen production in both reactors. Methanol and butyric, acetic, and lactic acids were the main metabolites at temperatures of 55 and 65 °C, favoring the butyric and acetic metabolic pathways of hydrogen production. The increased productions of lactate, propionate, and methanol at 75 °C indicate that the hydrogen-producing bacteria in the thermophilic inoculum were inhibited under hyperthermophilic conditions. [ABSTRACT FROM AUTHOR]

This study considered the application of anaerobic digestion (AD) with phase separation combined with the use of an anaerobic structured-bed reactor (ASTBR) as the methanogenic phase for the treatment of sugarcane vinasse, a high-strength wastewater resulting from ethanol production. Two combined thermophilic acidogenic-methanogenic systems formed by one single acidogenic reactor followed by two methanogenic reactors operated in parallel were compared, namely, a conventional UASB reactor and an upflow ASTBR reactor. Increasing organic loading rate (OLR) conditions (15–30 kg COD m −3 d −1 ) were applied to the methanogenic reactors. The results highlighted the feasibility of applying the ASTBR to vinasse, indicating a global COD removal higher than 80%. The ASTBR exhibited a stable long-term operation (240 days), even for OLR values as high as 30 kg COD m −3 d −1 . The application of similar conditions to the UASB reactor indicated severe performance losses, leading to the accumulation of acids for every increase in the OLR. An energetic potential of 181.5 MJ for each cubic meter of vinasse was estimated from both hydrogen and methane. The provision of bicarbonate alkalinity proved to be a key factor in obtaining stable performance, offsetting the limitations of relatively low hydraulic retention times (<24 h). [ABSTRACT FROM AUTHOR]

The post-treatment of biodigested sugarcane vinasse was envisaged in the present study following three different approaches: i) coagulation/flocculation – Approach 1; ii) combination of coagulation/flocculation with photo-Fenton reaction – Approach 2; iii) coagulation/flocculation followed by biological degradation and photo-Fenton reaction – Approach 3. The coagulation/flocculation per se provided a slight increase in effluent's biodegradability, a decrease in toxicity and turbidity, and provided moderate removals of total organic carbon (TOC), biochemical oxygen demand (BOD 5 ) and chemical oxygen demand (COD). The operating costs associated with chemicals consumption are low (5.7 R$/m 3 ≈ 1.4 €/m 3 ). The second and third treatment approaches allowed to reach a nontoxic effluent, improved the biodegradability and led to similar high global organics removal efficiencies. The combined treatment consisting of coagulation/flocculation plus photo-Fenton oxidation (Approach 2) revealed to be a promising solution for treating this wastewater, in order to be recirculated into the high rate anaerobic reactor. Additionally, this solution provides smaller costs (84.9 R$/m 3 ≈ 20.2 €/m 3 ) associated with chemicals and energy consumption, which are however very high. Nonetheless, this cost can be reduced by about 40% if solar radiation is used in the photo-Fenton process. [ABSTRACT FROM AUTHOR]

• The electrodialysis performance was stable even over longer operation times. • SEM/EDS/FTIR analyses indicated the efficiency of the chemical cleaning procedure. • Electrodialysis showed favorable performance operating with fewer compartments. • Desalted effluent streams showed no degree of restriction for use in fertigation. • Production of organo-mineral fertilizer brings economic and environmental benefits. Electrodialysis (ED) is reported as a promising technique for vinasse desalination and nutrients recovery for mineral (K-struvite) and organomineral fertilizers production. The use of ultrafiltered vinasse as an electrolyte solution, as well as fouling layer formation on membrane surface, were evaluated by operating the ED for a longer operation time. After 40 h of test time, it was observed that the ED performance was stable, with high efficiencies of removal (>77 %) and recovery (>70 %) of potassium. Ultrafiltered vinasse did not affect the efficiencies of nutrient removal and recovery, and provides as benefits a reduction in the costs of water and chemical demand, and the production of organo-mineral fertilizer. Membrane fouling was considerably reduced after the cleaning procedure. Also, ED operation was evaluated in three configurations, namely A, B, and C, with 5, 3, and 2 compartments, respectively. The lower number of compartments did not affect the ED performance, with similar performance as that observed for the Configuration A. Removal and recovery efficiencies for potassium, calcium and magnesium were similar in all experiments, being 80 and 72 %, 57 % and 49 %, 46 % and 8 %, respectively. For the specific energy consumption per mole of K+ (E/K+), no significant differences were found between the three configurations for both electrolyte solutions, being around 0.3049 ± 0.012 KWh/Kg K+. Of the configurations evaluated, Configuration C demonstrated to be a viable alternative for implementation in a biorefinery for sugarcane vinasse treatment. Besides the high performance presented, this configuration has advantages such as: reduction in energy use, membrane area, area required for system installation, water and chemical demand, and the potential recovery of gaseous chlorine, which can be used as a decolorizing agent. [ABSTRACT FROM AUTHOR]

Ethanol production has increased over the years, and Brazil ranking second in the world using sugarcane as the main raw material. However, 10–15 L of vinasse are generated per liter of ethanol produced. Besides large volumes, this wastewater has high polluting potential due to its low pH and high concentrations of organic matter and nutrients. Given the high biodegradability of the organic matter, the treatment of this effluent by anaerobic digestion and membrane separation processes results in the generation of high value-added byproducts such as volatile fatty acids (VFAs), biohydrogen and biogas. Membrane bioreactors have been widely evaluated due to the high efficiency achieved in vinasse treatment. In recent years, high retention membrane bioreactors, in which high retention membranes (nanofiltration, reverse osmosis, forward osmosis and membrane distillation) are combined with biological processes, have gained increasing attention. This paper presents a critical review focused on high retention membrane bioreactors and the challenges associated with the proposed configurations. For nanofiltration membrane bioreactor (NF-MBR), the main drawback is the higher fouling propensity due to the hydraulic driving force. Nonetheless, the development of membranes with high permeability and anti-fouling properties is uprising. Regarding osmotic membrane bioreactor (OMBR), special attention is needed for the selection of a proper draw solution, which desirably should be low cost, have high osmolality, reduce reverse salt flux, and can be easily reconcentrated. Membrane distillation bioreactor (MDBR) also exhibit some shortcomings, with emphasis on energy demand, that can be solved with the use of low-grade and residual heat, or renewable energies. Among the configurations, MDBR seems to be more advantageous for sugarcane vinasse treatment due to the lower energy consumption provided by the use of waste heat from the effluent, and due to the VFAs recovery, which has high added value. [Display omitted] • Sugarcane vinasse treatment reduces the environmental impact of ethanol production. • Wastewater treatment by HR-MBR enables water reuse and resources recovery. • Residual heat from vinasse can be used to reduce the energy demand in MD-MBRs. • Full-scale HR-MBR needs future research to make it economically viable. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrodialysis and chemical precipitation were used for potassium recovery from vinasse. • Electrodialysis showed stable performance with chemical precipitation supernatant recycling. • High removal of potassium (69%), phosphorus (92%), magnesium (88%) from chemical precipitation. • Vinasse desalination using electrodialysis reduces transportation costs for soil irrigation. • Proposed system shows feasible method for water saving and K-struvite fertilizer production. Brazil is the largest importer of potassium-based fertilizers, with Russia and Belarus accounting for 44% of these imports. However, recent events elevated the risk of disruptions in the global fertilizer trade. Thus, the nutrients recovery from potassium-rich industrial wastewater, such as sugarcane vinasse, can contribute to the conservation of natural resources and a guaranteed supply of the product. In this work, the integration of electrodialysis and chemical precipitation processes was evaluated for sugarcane vinasse treatment, aiming at potassium recovery and electrolyte solution recycling. The electrodialysis cathode concentrate was submitted to chemical precipitation to form K-struvite, while the supernatant from this step was recirculated to the cathode concentrate compartment for the next electrodialysis batch, for a total of 3 sequential electrodialysis-chemical precipitation batches. The electrolyte solution recycling implies a reduction in water consumption in the electrodialysis process. Also, through conducting sequential batches, it is possible to evaluate the number of consecutive times that the supernatant can be reused, maximizing the reduction in water consumption for the recovery of the maximum amount of nutrients, however without harming the electrodialysis performance. The electrodialysis presented stable performance throughout the three batches performed, with potassium removal efficiencies around 76% and recovery around 68%. As for the chemical precipitation step, the removal efficiencies of potassium, phosphorus, and magnesium were 69%, 92%, and 88%, respectively, with no significant differences from the Kruskal-Wallis test between the three batches. From the SEM/EDS and X-ray diffraction analyses, the formation of the K-struvite fertilizer in the precipitates was confirmed, leading to the production of 3.2 kg K-struvite/m3 of treated vinasse. The proposed system was suitable for water saving in the electrodialysis stage, recovery of K-struvite fertilizer, and increase in the vinasse application rate to the soil (equivalent to an increase of 330% in the maximum vinasse application rate), while reducing the costs with wastewater transportation for soil irrigation. Thus, this process integration could help a possible fertilizer supply shortage, reduce environmental impacts and reduce costs regarding the electrodialysis concentrate treatment. [ABSTRACT FROM AUTHOR]

The efficiency of individual and integrated processes applied to organic matter reduction and biodegradability improvement of a biodigested sugarcane vinasse wastewater was assessed. Strategies considered were Fenton’s oxidation (Strategy 1), coagulation/flocculation (Strategy 2) and the combination of both processes (coagulation/flocculation followed by Fenton’s reaction) – Strategy 3. It was found that Fenton’s oxidation per se allowed reducing the organic matter, increasing the wastewater biodegradability and a non-toxic effluent was generated; however the cost of treatment was very high (86.6 R$/m 3 – 21.2 €/m 3 ). Under optimized conditions, coagulation/flocculation provided a slight increase in effluent’s biodegradability, toxicity towards Vibrio fischeri was also eliminated and moderate removals of total organic carbon – TOC – (30.5%), biological oxygen demand – BOD 5 – (27.9%) and chemical oxygen demand – COD – (43.6%) were achieved; however, the operating costs are much smaller. The use of dissolved iron resulting from coagulation/flocculation (270 mg/L) as catalyst in the second stage – Fenton’s oxidation – was shown to be an innovative and economically attractive strategy. Under optimal conditions overall removals of 51.6% for TOC, 45.7% for BOD 5 and 69.2% for COD were achieved, and a biodegradable (BOD 5 :COD ratio = 0.54) and non-toxic effluent was obtained. In order to increase the efficiency of the process but using less hydrogen peroxide, the Fenton’s oxidation was performed by gradually adding the oxidant. This procedure allowed to obtain the highest organic matter removal efficiency (as compared with the addition of all hydrogen peroxide at the beginning of the reaction). This way it was possible to minimize the reagent consumption and, consequently, reduce the treatment cost. [ABSTRACT FROM AUTHOR]

In this study, the effects of nitrogen, phosphate and trace elements supplementation were investigated in a semi-continuously operated upflow anaerobic sludge blanket system to enhance process stability and biogas production from sugarcane vinasse. Phosphate in form of KH 2 PO 4 induced volatile fatty acids accumulation possibly due to potassium inhibition of the methanogenesis. Although nitrogen in form of urea increased the reactor’s alkalinity, the process was overloaded with an organic loading rate of 6.1 g COD L −1 d −1 and a hydraulic retention time of 3.6 days. However, by supplementing urea and trace elements a stable operation even at an organic loading rate of 9.6 g COD L −1 d −1 and a hydraulic retention time of 2.5 days was possible, resulting in 79% higher methane production rate with a stable specific methane production of 239 mL g COD −1 . [ABSTRACT FROM AUTHOR]

Although the use of saltbush plants in metal phytoremediation is well known, there is little information about the impact of sugarcane vinasse (SCV) and EDTA on metal uptake. Heavily cadmium-polluted soil (38 mg kg Cd) was used in pot and incubation experiments to investigate the Cd phytoextraction potential of wavy saltbush ( Atriplex undulata) and quail saltbush ( Atriplex lentiformis). EDTA at rates of 3, 6, and 10 mM kg soil and SCV at rates of 7, 15, and 30 mL kg soil were added to the polluted soil. The application of EDTA significantly ( P = 0.002) reduced the growth of saltbush plants; on the other hand, SCV improved the growth. Both EDTA and SCV increased the availability and root-to-shoot transfer of Cd. The plants of A. lentiformis grown on the soil amended with the highest rate of SCV were able to remove 20.4 % of the total soil Cd during a period of 9 months. Based on the obtained results, it may be concluded that A. lentiformis and sugarcane vinasse could be more effective in the phytoextraction of Cd from the polluted soils. [ABSTRACT FROM AUTHOR]

The feasibility of sugarcane vinasse as supplement in growth medium of Spirulina maxima was investigated. The cell was cultivated under autotrophic (no vinasse, 70 μmol photons m −2 s −1 ), heterotrophic (no light, culture medium supplemented with vinasse at 0.1% v/v and 1.0% v/v) and mixotrophic conditions (70 μmol photons m −2 s −1 , vinasse at 0.1% v/v and 1.0% v/v). These preliminary results suggested a cyclic two-stage cultivation – CTSC, with autotrophic condition during light phase of the photoperiod (12 h, 70–200 μmol photons m −2 s −1 ) and heterotrophic condition during dark phase (12 h, 3.0% v/v vinasse). The adopted CTSC strategy consisted in three cycles with 75% withdrawal of suspension and reposition of medium containing 3.0% v/v vinasse, separated by autotrophic rest periods of few days between cycles. Results show an increase of biomass concentration between 0.495 g L −1 and 0.609 g L −1 at the 7th day of each cycle and high protein content (between 74.3% and 77.3% w/w). [ABSTRACT FROM AUTHOR]

This study evaluated the influence of a high organic loading rate (OLR) on thermophilic hydrogen production at an up-flow anaerobic packed-bed reactor (APBR) treating a residual liquid stream of a Brazilian biorefinery. The APBR, filled with low-density polyethylene, was operated at an OLR of 84.2 kg-COD m −3 d −1 . This value was determined in a previous study. The maximum values of hydrogen production and yield were 5,252.6 mL-H 2 d −1 and 3.7 mol-H 2 mol −1 total carbohydrates , respectively. However, whereas the OLR remained constant, the specific organic load rate (sOLR) decreased throughout operation from 1.38 to 0.72 g-Total carbohydrates g-VS −1 h −1 , this decrease negatively affected hydrogen production. A sOLR of 0.98 g-Total carbohydrates g-VS −1 h −1 was optimal for hydrogen production. The microbial community was studied using 454-pyrosequencing analysis. Organisms belonging to the genera Caloramator , Clostridium, Megasphaera , Oxobacter , Thermoanaerobacterium , and Thermohydrogenium were detected in samples taken from the reactor at operation days 30 and 60, suggesting that these organisms contribute to hydrogen production. [ABSTRACT FROM AUTHOR]

The major wastewater of ethanol production plants from sugarcane, i.e., vinasse, is a severe environmental pollutant and challenges sustainable cane-based biofuel production. The potential of anaerobic digestion (AD) of vinasse is well demonstrated; however, the digestion process requires special operational conditions that severely affect biodegradation. The main affecting parameters are pH, temperature, nutrients, carbon-to-nitrogen ratio, and the presence of inhibitors. Besides, oxidation-reduction potential, hydraulic retention time (HRT), organic loading rate (OLR), mixing, and reactor configurations are among the influencing factors. In this study, the effects of reactor configurations on biogas production from vinasse are comprehensively investigated, and the perspectives are discussed. The up-flow anaerobic sludge blanket, expanded granular sludge bed, fixed bed reactor (packed-bed and structured-bed), and hybrid anaerobic reactor are configurations used for vinasse treatment. The up-flow anaerobic sludge blanket, the most popular reactor used, has a high reaction rate and performance at low HRT levels; however, washout and reactor stability are typical issues in industrial-scale applications. Among single-stage reactors, hybrid anaerobic reactor configurations have more stability and high performance. Despite enormous efforts, more studies need to optimize the operating conditions and more information at pilot scale is necessary for the industrialization of the processes. [Display omitted] • UASB reactors are the most common systems tested in sugarcane vinasse AD. • Deficient granulation due to excess solids is the main bottleneck in UASB reactors. • High-porosity fixed-film reactors are suitable configurations for vinasse AD. • Hybrid technologies (sludge bed + fixed-film) have also potential to be exploited. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of organic loading rate (OLR) on hydrogen production in up-flow anaerobic packed bed reactors (APBR) continuously fed with sugarcane vinasse. Four thermophilic up-flow APBR were operated in parallel at different ORL. Continuous hydrogen production was detected. The optimum OLR of 84.2 kg-COD m −3 d −1 was assessed by polynomial adjustment, which predicted a maximum Volumetric Hydrogen Production (VHP) and hydrogen yield ( Y H 2 ) of 1117.2 mL-H 2 d −1 L −1 reactor and 2.4 mol-H 2 mol −1 total carbohydrates , respectively. The microbial composition was monitored using 16S rRNA gene by Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis and quantification of Fe-hydrogenase gene by real-time PCR which was affected by the OLR. The number of the Fe-hydrogenase genes was proportional to the monitored hydrogen production and yield. Hydrogen-producing strains were isolated, and the 16S rRNA gene sequences were highly homologous to those of Thermoanaerobacterium thermosaccarolyticum . The ability of vinasse as substrate for hydrogen production was confirmed for both strains. [ABSTRACT FROM AUTHOR]

This study evaluated an anaerobic fluidized bed reactor (AFBR) that contained polystyrene particles as a support material for the treatment of vinasse that resulted from the alcoholic fermentation of sugarcane molasses. The AFBR was inoculated with sludge from an upflow anaerobic sludge blanket reactor that treated poultry slaughterhouse wastewater. The AFBR was operated with a hydraulic retention time of 24 h at a temperature of 30°C with influent vinasse concentrations that ranged from 2273 to 20,073 mg COD L−1. The reactor was subjected to increased organic loading rates (OLR) that ranged from 3.33 to 26.19 kg COD m−3d−1, with COD removal efficiencies that ranged from 51% to 70% and maximum removal at an OLR of 13.93 ± 2.18 kg COD m−3d−1. The maximum biogas productivity was 5.37 m3CH4m−3d−1for an OLR of 25.32 kg COD m−3d−1(average removal of 51%)., [ABSTRACT FROM AUTHOR]