Batch and semi-continuous treatment of cassava wastewater using microbial fuel cells and metataxonomic analysis.

The treatment of agroindustrial wastewater using microbial fuel cells (MFCs) is a technological strategy to harness its chemical energy while simultaneously purifying the water. This manuscript investigates the organic load effect as chemical oxygen demand (COD) on the production of electricity during the treatment of cassava wastewater by means of a dual-chamber microbial fuel cell in batch mode. Additionally, specific conditions were selected to evaluate the semi-continuous operational mode. The dynamics of microbial communities on the graphite anode were also investigated. The maximum power density delivered by the batch MFC (656.4 µW m - 2 ) was achieved at the highest evaluated organic load (6.8 g COD L - 1 ). Similarly, the largest COD removal efficiency (61.9%) was reached at the lowest organic load (1.17 g COD L - 1 ). Cyanide degradation percentages (50-70%) were achieved across treatments. The semi-continuous operation of the MFC for 2 months revealed that the voltage across the cell is dependent on the supply or suspension of the organic load feed. The electrode polarization resistance was observed to decreases over time, possibly due to the enrichment of the anode with electrogenic microbial communities. A metataxonomic analysis revealed a significant increase in bacteria from the phylum Firmicutes, primarily of the genus Enterococcus.

Cassava wastewater valorization for the production of biosurfactants: surfactin, rhamnolipids, and mannosileritritol lipids.

The global production of cassava was estimated at ca. 303 million tons. Due to this high production, the cassava processing industry (cassava flour and starch) generates approximately ca. 0.65 kg of solid residue and ca. 25.3 l of wastewater per kg of fresh processed cassava root. The composition of the liquid effluent varies according to its origin; for example, the effluent from cassava flour production, when compared to the wastewater from the starch processing, presents a higher organic load (ca. 12 times) and total cyanide (ca. 29 times). It is worthy to highlight the toxicity of cassava residues regarding cyanide presence, which could generate disorders with acute or chronic symptoms in humans and animals. In this sense, the development of simple and low-cost eco-friendly methods for the proper treatment or reuse of cassava wastewater is a challenging, but promising path. Cassava wastewater is rich in macro-nutrients (proteins, starch, sugars) and micro-nutrients (iron, magnesium), enabling its use as a low-cost culture medium for biotechnological processes, such as the production of biosurfactants. These compounds are amphipathic molecules synthesized by living cells and can be widely used in industries as pharmaceutical agents, for microbial-enhanced oil recovery, among others. Amongst these biosurfactants, surfactin, rhamnolipids, and mannosileritritol lipids show remarkable properties such as antimicrobial, biodegradability, demulsifying and emulsifying capacity. However, the high production cost restricts the massive biosurfactant applications. Therefore, this study aims to present the state of the art and challenges in the production of biosurfactants using cassava wastewater as an alternative culture medium.

Effect of initial pH and substrate concentration on the lactic acid production from cassava wastewater fermentation by an enriched culture of acidogenic microorganisms.

Recently, cassava processing wastewater has been considered an alternative substrate for lactic acid production due to its appreciable carbohydrate levels. The authors carried out different batch reactor trials aiming to favor the production of lactic acid through the fermentation of non-sterilized cassava wastewater by an enriched culture of acidogenic microorganisms. To this end, the impact of different initial pHs (4.5, 5.0, 5.7, 6.5, and 7.0) and different initial substrate concentrations (10, 15.8, 30, 44.2, and 50 g/L) in terms of glucose on lactic acid production yield (Y) was evaluated by applying the design of experiment (DoE) known as central composite rotatable design (CCRD). The highest rate of lactic acid production (40 g/L) occurred with an initial pH of 6.5 and an initial substrate concentration of 50 g/L. The maximum yield was higher in trials T1, T2, T4, T5, and T8, reaching values of 0.80, 0.62, 0.60, 0.96, and 0.70 g/g, respectively. The maximum lactic acid productivity (P), of 0.60 and 0.73 g L-1  hr-1 , was observed in trials T5 and T8, respectively. The enriched culture of acidogenic microorganisms was shown to favor the production of lactic acid, since the production of other acids, such as acetic and propionic acid, did not exceed 3.5 and 4.5 g/L, respectively. © 2020 Water Environment Federation PRACTITIONER POINTS: Cassava wastewater presented potential to lactic acid production. The CCRD showed that highest lactic acid concentrations (40 g/L). The adoption of cassava wastewater or manipueira as a substrate resulted in important information on the tendency to obtain value-added products such as lactic acid.

Influence of spontaneous fermentation of manipueira on bioactive amine and carotenoid profiles during tucupi production.

Tucupi is a kind of broth that is common to the Amazonian region of Brazil, which is produced after the spontaneous fermentation and boiling of manipueira, a liquid by-product extracted from cassava roots during cassava flour production. The bioactive amines formation and their alterations during tucupi processing were investigated for the first time. In addition, the physicochemical changes, instrumental color parameters and carotenoid profile were monitored during tucupi production. Regarding the changes on the profile of carotenoids, all-trans-ß-carotene was the major carotenoid, followed by its 9- and 13-cis isomers, and this profile was not altered throughout the process. Spermidine (polyamine), putrescine, tyramine and histamine (biogenic amines) were the bioactive amines identified during the tucupi production process, but at low levels (0.76-7.24 mg/L). Principal Component Analysis suggested three distinct stages during tucupi production: the first stage was characterized by the manipueira up to 12 h of fermentation with the highest values of pH, total and reducing sugars, and total starch; the second stage refers to the end of the fermentation process (16 to 24 h), in which biogenic amines (histamine and tyramine) were produced; and the third stage was characterized by the final product (tucupi), with the highest values of total acidity, soluble solids, polyamines and tyramine. Therefore, the results suggest the need of an accurate control of the fermentation of the manipueira to avoid or minimize the formation of biogenic amines.

Powdered tucupi condiment: sensory and hygroscopic evaluation

Abstract Tucupi is a fermented liquid obtained from cassava (Manihot esculenta Crantz), very much appreciated by the traditional cuisine of Northern Brazil. However, there are no scientific reports on its use in the formulation of products. Thus, the present study aimed to elaborate a powdered condiment with tucupi, as well as to assess the product's sensory acceptability and its hygroscopic behavior. The powdered tucupi used in the formulation of the condiment was obtained by drying in a spray dryer. The product underwent sensory evaluation for its acceptability regarding the attributes of color, aroma, flavor, and overall impression and a purchase intention test was applied by hedonic scale. The acceptability index was 80% for overall impression and the purchase intention test indicated that 94% of the judges would be willing to buy the product. The product's moisture sorption isotherms presented type-II behavior for adsorption and type-III for desorption, at 25 °C. The hygroscopic behavior indicated that the product is more susceptible to spoilage changes when stored in an environment with relative humidity above 60% and the Peleg model showed an excellent performance on predicting the product's moisture sorption isotherms.

Apparent digestibility and rumen protozoal profile of sheep fed cassava wastewater / Digestibilidade aparente e perfil de protozoários no rúmen em ovinos alimentados com manipueira

The effects of cassava wastewater on nutrient digestibility and rumen protozoa were evaluated in 32 Santa Inês sheep fed a diet with Tifton hay, ground corn cob, and concentrate, containing 0, 500, 1000, or 1500 mL cassava wastewater. Uncastrated sheep at an average age of 167 days and average weight of 25.3 kg were housed in individual stalls and distributed in a randomized complete design with four treatments and eight replicates. The experimental period was 70 days: 15 days for adaptation to the diets and 60 days to collect the ingredients and diets supplied. Prior to this stage, the animals were adapted to the consumption of cassava wastewater, in collective cages, for seven days. Apparent digestibility was determined by partial feces collection and by using the LIPE® external marker in 250-mg capsules. The apparent digestibility of nutrients did not differ (P>0.05) in relation to the cassava wastewater levels tested. Eleven genera of rumen protozoa were identified, and they formed a community that, except for Ophryoscolex, did not differ among the cassava wastewater treatments with respect to composition. However, Entodinium species were observed at a higher density (P<0.05) in sheep that received 1500 mL of cassava wastewater. The use of cassava wastewater in the sheep diet does not affect the digestibility of nutrients or composition of rumen protozoa; however, it causes a significant increase in Entodinium density.

Os efeitos da manipueira sobre a digestibilidade de nutrientes e protozoários ruminais foram avaliados utilizando-se 32 ovinos Santa Inês submetidos a dietas compostas por feno de Tifton, rolão de milho e concentrado, acrescidas de 0, 500, 1000 ou 1500 mL de manipueira. Foram utilizados ovinos não castrados com idade media de 167 dias e com peso médio e aproximadamente 25,3 kg. Foram alojados em gaiolas individuais e distribuídos em delineamento inteiramente casualizado com quatro tratamentos e oito repetições. O período experimental foi de 70 dias: 15 dias para adaptação às dietas e 60 dias para coleta dos ingredientes e rações. Antes desta fase, os animais foram adaptados ao consumo de manipueira em gaiolas coletivas durante um período de 7 dias. A digestibilidade aparente foi determinada pela coleta parcial de fezes e pelo uso do marcador externo LIPE® em cápsulas de 250 mg. A digestibilidade aparente dos nutrientes avaliados não diferiu (P>0,05) em relação aos níveis de manipueira estudados. Onze gêneros de protozoários foram identificados, compondo uma comunidade que à exceção de Ophryoscolex, não diferiu entre os tratamentos em sua composição. Entretanto, as espécies de Entodiniumapresentaram maior densidade (P<0,05) em ovinos que receberam 1500 mL de manipueira. O uso da manipueira na dieta de ovinos não afeta a digestibilidade de nutrientes e composição de protozoários ruminais, entretanto, promove aumento significativo na densidade de Entodinium.

Apparent digestibility and rumen protozoal profile of sheep fed cassava wastewater / Digestibilidade aparente e perfil de protozoários no rúmen em ovinos alimentados com manipueira

The effects of cassava wastewater on nutrient digestibility and rumen protozoa were evaluated in 32 Santa Inês sheep fed a diet with Tifton hay, ground corn cob, and concentrate, containing 0, 500, 1000, or 1500 mL cassava wastewater. Uncastrated sheep at an average age of 167 days and average weight of 25.3 kg were housed in individual stalls and distributed in a randomized complete design with four treatments and eight replicates. The experimental period was 70 days: 15 days for adaptation to the diets and 60 days to collect the ingredients and diets supplied. Prior to this stage, the animals were adapted to the consumption of cassava wastewater, in collective cages, for seven days. Apparent digestibility was determined by partial feces collection and by using the LIPE® external marker in 250-mg capsules. The apparent digestibility of nutrients did not differ (P>0.05) in relation to the cassava wastewater levels tested. Eleven genera of rumen protozoa were identified, and they formed a community that, except for Ophryoscolex, did not differ among the cassava wastewater treatments with respect to composition. However, Entodinium species were observed at a higher density (P<0.05) in sheep that received 1500 mL of cassava wastewater. The use of cassava wastewater in the sheep diet does not affect the digestibility of nutrients or composition of rumen protozoa; however, it causes a significant increase in Entodinium density.(AU)

Os efeitos da manipueira sobre a digestibilidade de nutrientes e protozoários ruminais foram avaliados utilizando-se 32 ovinos Santa Inês submetidos a dietas compostas por feno de Tifton, rolão de milho e concentrado, acrescidas de 0, 500, 1000 ou 1500 mL de manipueira. Foram utilizados ovinos não castrados com idade media de 167 dias e com peso médio e aproximadamente 25,3 kg. Foram alojados em gaiolas individuais e distribuídos em delineamento inteiramente casualizado com quatro tratamentos e oito repetições. O período experimental foi de 70 dias: 15 dias para adaptação às dietas e 60 dias para coleta dos ingredientes e rações. Antes desta fase, os animais foram adaptados ao consumo de manipueira em gaiolas coletivas durante um período de 7 dias. A digestibilidade aparente foi determinada pela coleta parcial de fezes e pelo uso do marcador externo LIPE® em cápsulas de 250 mg. A digestibilidade aparente dos nutrientes avaliados não diferiu (P>0,05) em relação aos níveis de manipueira estudados. Onze gêneros de protozoários foram identificados, compondo uma comunidade que à exceção de Ophryoscolex, não diferiu entre os tratamentos em sua composição. Entretanto, as espécies de Entodiniumapresentaram maior densidade (P<0,05) em ovinos que receberam 1500 mL de manipueira. O uso da manipueira na dieta de ovinos não afeta a digestibilidade de nutrientes e composição de protozoários ruminais, entretanto, promove aumento significativo na densidade de Entodinium.(AU)

Performance of an Anaerobic Baffled Reactor (ABR) in treatment of cassava wastewater / Desempenho de um Reator Anaeróbio Compartimentado (RAC) no tratamento da manipueira

The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater, a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35ºC was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000 mg L-1 and it was evaluated the most appropriated hydraulic retention time (HRT) for the best performance on COD removal. The ABR was evaluated by analysis of COD (colorimetric method), pH, turbidity, total and volatile solids, alkalinity and acidity. Principal component analysis (PCA) was carried to better understand data obtained. The system showed buffering ability as acidity decreased along compartments while alkalinity and pH values were increased. There was particulate material retention and COD removal varied from 83 to 92% for HRT of 3.5 days.

O desempenho de um reator anaeróbio compartimentado (RAC) foi avaliado para o tratamento da manipueira, resíduo tóxico. Um RAC dividido em quatro compartimentos de mesmo volume (volume total 4L) e operado a 35ºC foi utilizado no tratamento da manipueira. A demanda química de oxigênio (DQO) do tanque de alimentação variou de 2000 a 7000 mg L-1 e avaliou-se o tempo de residência hidráulica (TRH) mais apropriado ao melhor desempenho do reator. O RAC foi avaliado pelas análises de DQO (método colorimétrico), pH, turbidez, sólidos totais e voláteis, alcalinidade e acidez. A Análise das Componentes Principais (PCA) foi conduzida para melhor compreensão dos dados obtidos. O sistema apresentou capacidade tamponante conforme a acidez decresceu ao longo dos compartimentos ao passo que a alcalinidade e o pH aumentaram. Houve retenção do material particulado e a remoção da DQO variou de 83 a 92% para TRH de 3,5 dias.

Performance of an Anaerobic Baffled Reactor (ABR) in treatment of cassava wastewater.

The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater, a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35ºC was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000 mg L(-1) and it was evaluated the most appropriated hydraulic retention time (HRT) for the best performance on COD removal. The ABR was evaluated by analysis of COD (colorimetric method), pH, turbidity, total and volatile solids, alkalinity and acidity. Principal component analysis (PCA) was carried to better understand data obtained. The system showed buffering ability as acidity decreased along compartments while alkalinity and pH values were increased. There was particulate material retention and COD removal varied from 83 to 92% for HRT of 3.5 days.

Performance of an Anaerobic Baffled Reactor (ABR) in treatment of cassava wastewater

The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater, a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35°C was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000 mg L-1 and it was evaluated the most appropriated hydraulic retention time (HRT) for the best performance on COD removal. The ABR was evaluated by analysis of COD (colorimetric method), pH, turbidity, total and volatile solids, alkalinity and acidity. Principal component analysis (PCA) was carried to better understand data obtained. The system showed buffering ability as acidity decreased along compartments while alkalinity and pH values were increased. There was particulate material retention and COD removal varied from 83 to 92% for HRT of 3.5 days.

O desempenho de um reator anaeróbio compartimentado (RAC) foi avaliado para o tratamento da manipueira, resíduo tóxico. Um RAC dividido em quatro compartimentos de mesmo volume (volume total 4L) e operado a 35°C foi utilizado no tratamento da manipueira. A demanda química de oxigênio (DQO) do tanque de alimentação variou de 2000 a 7000 mg L-1 e avaliou-se o tempo de residência hidráulica (TRH) mais apropriado ao melhor desempenho do reator. O RAC foi avaliado pelas análises de DQO (método colorimétrico), pH, turbidez, sólidos totais e voláteis, alcalinidade e acidez. A Análise das Componentes Principais (PCA) foi conduzida para melhor compreensão dos dados obtidos. O sistema apresentou capacidade tamponante conforme a acidez decresceu ao longo dos compartimentos ao passo que a alcalinidade e o pH aumentaram. Houve retenção do material particulado e a remoção da DQO variou de 83 a 92% para TRH de 3,5 dias.

Selection of microorganisms for biosurfactant production using agroindustrial wastes

Biosurfactant production by some bacterial isolates using molasses, milk whey and cassava flour wastewater (manipueira) as substrates was evaluated and compared with the production in conventional medium. Isolates growing in manipueira medium decreased the surface tension around 42%, the highest reduction among all the substrates tested. From the eleven isolates tested, eight were able to decrease the surface tension to levels below 30 mN/m using manipueira as substrate. The isolates LB5a, LB2a, LB262, LBB and LB1a that gave surface tension about 26 mN/m were identified as Bacillus sp. Natural manipueira (high solids content) and decanted manipueira (no solids) were investigated as culture media for biosurfactant production by selected microorganisms. Natural manipueira medium showed minimum surface tension of 28 mN/m (LB5a isolate) whereas for decanted manipueira the lowest value was 26 mN/m (isolate LB2a). Average diameter of growth on manipueira agar was 7.2 cm for isolate LB5a suggesting a high growth capacity on this substrate. Manipueira comprises a potential alternative culture medium for biosurfactant production by the selected isolates.

Alguns isolados bacterianos foram avaliados quanto à capacidade de produção de biossurfatantes a partir de melaço, soro de leite e manipueira como substratos. A produção nestes meios alternativos foi comparada com a produção em meio de cultura convencional. Dentre os meios testados, a manipueira demonstrou a maior percentagem de redução na tensão superficial atingindo valores ao redor de 42%. Dos onze isolados testados, oito foram capazes de diminuir a tensão superficial para níveis inferiores à 30mN/m utilizando manipueira como substrato. Os isolados LB 5a, LB2a, LB262, LBB e LB1a apresentaram tensão superficial em torno de 26 mN/m sendo selecionados e posteriormente identificados como pertencentes ao gênero Bacillus sp. A manipueira natural (alto teor de sólidos) e a manipueira decantada (ausência de sólidos) foram investigadas como meios de cultivo para produção de biossurfatantes pelos microrganismos selecionados. O meio de manipueira natural apresentou tensão superficial minima de 28 mN/m (isolado LB5a) enquanto que o meio de manipueira decantada apresentou tensão superficial mínima de 26 mN/m (isolado LB2a). O diâmetro de crescimento médio do isolado LB5a em ágar manipueira foi de 7.2 cm sugerindo maior capacidade de crescimento neste substrato. A manipueira demonstrou potencial como meio de cultura alternativo para a produção de biossurfatantes pelos isolados selecionados.

Selection of microorganisms for biosurfactant production using agroindustrial wastes

Biosurfactant production by some bacterial isolates using molasses, milk whey and cassava flour wastewater (manipueira) as substrates was evaluated and compared with the production in conventional medium. Isolates growing in manipueira medium decreased the surface tension around 42%, the highest reduction among all the substrates tested. From the eleven isolates tested, eight were able to decrease the surface tension to levels below 30 mN/m using manipueira as substrate. The isolates LB5a, LB2a, LB262, LBB and LB1a that gave surface tension about 26 mN/m were identified as Bacillus sp. Natural manipueira (high solids content) and decanted manipueira (no solids) were investigated as culture media for biosurfactant production by selected microorganisms. Natural manipueira medium showed minimum surface tension of 28 mN/m (LB5a isolate) whereas for decanted manipueira the lowest value was 26 mN/m (isolate LB2a). Average diameter of growth on manipueira agar was 7.2 cm for isolate LB5a suggesting a high growth capacity on this substrate. Manipueira comprises a potential alternative culture medium for biosurfactant production by the selected isolates.

Alguns isolados bacterianos foram avaliados quanto à capacidade de produção de biossurfatantes a partir de melaço, soro de leite e manipueira como substratos. A produção nestes meios alternativos foi comparada com a produção em meio de cultura convencional. Dentre os meios testados, a manipueira demonstrou a maior percentagem de redução na tensão superficial atingindo valores ao redor de 42%. Dos onze isolados testados, oito foram capazes de diminuir a tensão superficial para níveis inferiores à 30mN/m utilizando manipueira como substrato. Os isolados LB 5a, LB2a, LB262, LBB e LB1a apresentaram tensão superficial em torno de 26 mN/m sendo selecionados e posteriormente identificados como pertencentes ao gênero Bacillus sp. A manipueira natural (alto teor de sólidos) e a manipueira decantada (ausência de sólidos) foram investigadas como meios de cultivo para produção de biossurfatantes pelos microrganismos selecionados. O meio de manipueira natural apresentou tensão superficial minima de 28 mN/m (isolado LB5a) enquanto que o meio de manipueira decantada apresentou tensão superficial mínima de 26 mN/m (isolado LB2a). O diâmetro de crescimento médio do isolado LB5a em ágar manipueira foi de 7.2 cm sugerindo maior capacidade de crescimento neste substrato. A manipueira demonstrou potencial como meio de cultura alternativo para a produção de biossurfatantes pelos isolados selecionados.