Global warming and the increase in organic waste from agro-industries create a major problem for the environment. In this sense, microbial fuel cells (MFC) have great potential for the generation of bioelectricity by using organic waste as fuel. This research produced low-cost MFC by using zinc and copper electrodes and taking blueberry waste as fuel. A peak current and voltage of 1.130 ± 0.018 mA and 1.127 ± 0.096 V, respectively, were generated. The pH levels were acid, with peak conductivity values of 233. 94 ± 0.345 mS/cm and the degrees Brix were descending from the first day. The maximum power density was 3.155 ± 0.24 W/cm2 at 374.4 mA/cm2 current density, and Cándida boidinii was identified by means of molecular biology and bioinformatics techniques. This research gives a new way to generate electricity with this type of waste, generating added value for the companies in this area and helping to reduce global warming.

In this study, we aimed to determine the in vitro activity of Leuconostoc mesenteroides var. mesenteroides isolatedfrom sugar-industry effluents to produce a dextran bioflocculant from sucrose as a low-cost substrate.L. mesenteroides strains present in residual cane juice from a sugar factory were isolated and biochemicallyidentified using Mayeux, Sandine, and Elliker agar (MSE) as a selective medium. The strain number 3 (LM03) wasbiochemically identified as L. mesenteroides var. mesenteroides, which was used for this study. The concentrationof dextran was quantified by dry weight, the morphology and purity were evaluated using Fourier-transforminfrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy(EDS). Flocculation was evaluated via turbidimetric assays in different pH ranges from sugar-industry effluentsand doses of dextran.To evaluate the flocculant activity according to the effect of pH, a jar test kit from Phipps and Bird, USA, wasused with the sample recollected from the effluent (sugar industry). The pH of the samples was adjusted to 7, 8,9, 10 and 11, with a dose of 40 ppm (dextran dose) at a fast and slow speed of 150 and 50 rpm, respectively. Toevaluate the influence of the dose of dextran, values of 5, 20 and 40 ppm were used with fast speeds of 180–150rpm and slow speeds of 30–50 rpm, respectively.The strain (LM03) was able to produce the highest concentration of dextran (26.87 g/L) in 76 h of incubation. Thepresence of dextran was identified in the MSE agar after incubation and characterized by FTIR, SEM, and EDS.Besides that, we observed that the best flocculation activity was observed at a pH of 9 and a concentration of 40ppm of dextran, with a fast agitation speed of 150 rpm for 5 min and a slow agitation speed of 50 rpm for 15 min,achieving 77.7% removal of turbidity from the sugar factory effluent.L. mesenteroides was responsible for the bioflocculation of dextran in different sugar-industry effluents

El efluente del proceso del curtido genera impactos negativos en la salud y el ambiente debido a que en esta etapa solo se aprovecha el 70% del cromo (Cr) total utilizado; por lo cual la bioadsorción surge como una alternativa en la remoción de metales pesados. En tal sentido, el objetivo de la presente investigación fue evaluar la capacidad de remoción de cromo en efluentes de curtiembre utilizando un consorcio de levaduras constituido por cepas de Saccharomyces cerevisiae (S) y Pichia guilliermondi (P) aislados de residuos agroindustriales. El diseño experimental consistió en 4 biorreactores de 250 ml condicionados con muestras de efluente de la etapa de curtido, teniendo como sorbente el consorcio (S+P), controlados a 0,6, 12 y 24 horas. Las muestras fueron analizadas por la técnica de espectrofotometría de absorción atómica a la flama. Los resultados muestran una capacidad de remoción de Cr total de 57% y 54% en concentración de 50 y 100 ppm respectivamente por el consorcio de levaduras; asimismo, la evaluación estadística con ANOVA permite afirmar que no existe diferencia significativa (p>0.05) al emplear ambas concentraciones, recomendándose el uso de la más alta en el proceso de bioadsorción de efluentes de curtiembres.

Polyhydroxyalkanoates (PHA) are biodegradable biopolymers of microbial origin that can be alternative materials to decrease the extensive use of plastics of petrochemical or synthetic origin. Thus, the selection of microorganisms with potential for PHA production from unexplored natural sources is a strategy to find bacterial species of high value. In the current study, 55 microbial strains related to bacteria were isolated from agricultural soils from Cascas, Peru. Initially, 4 strains were selected by Sudan Black B staining and Nile blue A fluorescence methods, subsequently, they were screened to examine its production capacity of PHA. Bacillus thuringiensis SP7-1 strain was selected based on its high production of PHA at 0.54 ± 0.16 g/L with an accumulation of 19 % by weight of cell biomass, during 72 h at 30 ºC. The isolate was characterized by its morphology, biochemical and molecular tests through the 16S rRNA gene. The extracted HIGHLIGHTS• Bacillus thuringiensis SP7-1 from agricultural soils producing polyhydroxyalkanoate.• The strains SP7-1 with a PHA accumulation of 0.54 g/L and 19 % in dry biomass.• PHA was characterized with FTIR, DSC and TGA with remarkable chemical properties.• A thermic degradation in a range of 270-303°C and a Melting Temperature of 166.88°C.

El objetivo fue aislar bacterias ácidas lácticas (BAL), productoras de biofloculante, a partir del jugo de caña residual. Por ello, las muestras de jugo de caña se obtuvieron a partir de 15 muestras de tallo de caña residual muestreadas al azar. Luego se procedio al asilamiento de las BAL mediante técnicas de microbiología convencional, para lo cual se empleó el medio de cultivo Agar Mayeux, Sandine y Elliker (MSE) a pH 7.2 y un tiempo de incubación de 30°C por 48 horas. Posterioremente, se realizó los cultivos puros a partir de las colonias características de Leuconostoc mesenteroides (colonias gomosas, viscosas, traslucidas y cremosas) para su identificación bioquímica de acuerdo al Manual de determinacion bacteriológica de Bergey’s. Para la identificación y selección de L. mesenteroides subsp. mesenteroides se realizó de acuerdo al método estadístico coeficiente Kappa, con la finalidad de utilizarla en la producción de dextrano (bioflcoulante) en un biorreactor aireado-agitado (Marca Aplikon). La pureza del dextrano se realizó mediante la técnica FT-IR el cual se comparó con el espectro de dextrano puro producido por la cepa NRRL P-640. Se logró aislar 4 cepas de Leuconostoc mesenteroides, LM (01-04), de las cuales la cepa LM03 se identificó como L. meenteroides subsp. mesenteroides. Los valores de dextrano producidos por LM03 fueron de 26.87 g/L a las 80 horas (concentración máxima) y 2.61 g/L a las 4 horas (concentración minima). El dextrano producido por LM03 es puro de acuerdo al análisis FT-IR. En conclusión, se logró aislar a la BAL L. mesenteroides subsp. mesenteroides (cepa LM03), la cual tuvo la capacidad de producir dextrano, el cual puede ser utilizado como biofloculante con distintos usos biotecnológicos e industriales.