Abstract This work aimed to assess the effectiveness of utilizing Rhizopus oryzae for starch hydrolysis from Porva corn (Zea mays) by evaluating different conditions during the fungus growth process in solid-state fermentation and enzymatic hydrolysis. The goal is to propose a potential methodology to produce commodities like beer, bypassing the traditional grain malting phase. Solid-state fermentation (SSF) was employed to analyze fungal growth on cereal cooked at distinct time intervals (0 min, 30 min, and 60 min) over 72 hours, maintaining an incubation temperature of 32 ºC. Subsequent enzymatic hydrolysis, conducted in the liquid phase at different temperatures (32 ºC, 44 ºC, and 56 ºC) for 5 hours, aimed to extract maximum fermentable sugars. Parameters such as cell concentration, reducing sugars, and dissolved solids (ºBrix) were measured. Furthermore, solid samples obtained at each stage underwent Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy analysis to identify changes in the composition of maize that occurred in each phase. The results indicate that the growth phase exhibited a significantly higher cell concentration of R. oryzae when corn was subjected to a 60-minute cooking pre-treatment. Conversely, the most favorable conditions for glucose concentration were observed during the hydrolysis phase at a temperature of 56 ºC, reaching up to 307 mgglucose/gcorn (51.23% of hydrolyzed starch). Subsequently, the obtained hydrolysate underwent fermentation for 84 hours using commercial yeast (Saccharomyces cerevisiae), resulting in a corn-based ferment with an alcohol content of 12% ABV, demonstrating that the process has good application potential in the manufacture of alcoholic beverages. Zea mays solidstate state beer Solidstate Solid SSF (SSF 0 ( min 3 6 7 ºC (3 4 sugars ºBrix (ºBrix measured Furthermore FTIR (FTIR R 60minute minute pretreatment. pretreatment pre treatment. treatment pre-treatment Conversely mgglucosegcorn mgglucose gcorn 51.23% 5123 51 23 (51.23 starch. . starch) Subsequently 8 Saccharomyces cerevisiae, cerevisiae , cerevisiae) cornbased based 12 ABV beverages 51.23 512 2 (51.2 1 51.2 (51. 51. (51 (5

Se llevaron a cabo procesos de biodesulfurización de dos carbones colombianos ricos en azufre ("Mina Vieja" y "Vampiro"), en reactores de lecho empacado a nivel de erlenmeyer, utilizando un consorcio de Acidithiobacillus ferrooxidans (ATCC 23270) y Acidithiobacillus thiooxidans (ATCC 15494), evaluando la adición de cisteína a la solución lixiviante. Los ensayos fueron monitoreados por medidas de hierro en solución, pH y potencial redox. Adicionalmente, se hicieron análisis mineralógicos por difracción de rayos X (DRX) antes y después de los experimentos. Los ensayos sin adición de cisteína alcanzaron una oxidación de pirita de 45.3% y 57.9% para "Mina Vieja" y "Vampiro" respectivamente. Cuando se adicionó cisteína, la oxidación aumentó en 14.9% para "Mina Vieja" y 6.4% para "Vampiro". Por otra parte, todos los ensayos evidenciaron remoción de caolinita, debido a su interacción con el ácido sulfúrico del medio. Con base en los resultados obtenidos, los componentes del carbón influenciaron tanto crecimiento bacteriano como la eficiencia de la cisteína sobre el grado de pirita oxidada.

Biodesulphurization processes of a two sulphur-rich coals from Colombia ("Mina Vieja" y "Vampiro") were carried out at packed-bed reactors at erlenmeyer level, using a consortium of Acidithiobacillus ferrooxidans (ATCC 23270) and Acidithiobacillus thiooxidans (ATCC 15494). Cysteine addition were evaluated. The assays were monitored by measurements of iron content, pH, and redox potential. X-ray diffraction (XRD) were used to establish the mineralogy before and after the process. The assays without cysteine respectively reached a pyrite oxidation of 45.3% ("Mina Vieja") and 57.9% ("Vampiro") after 38 days. Cysteine addition improved pyrite oxidation by 14.9% ("Mina Vieja") and 6.4% ("Vampiro"). On the other hand, all the assays removed kaolinite by interaction with sulphuric acid of the media. In base to the results, coal compounds influence bacterial growth and affects the efficiency of cysteine over pyrite oxidation.

Se evaluó el efecto de un medio de sales cloruros para un consorcio de Acidithiobacillus ferrooxidans y Acidithiobacillus thiooxidans en un proceso de biodesulfurización de un carbón colombiano (azufre total: 2.34%, azufre pirítico: 1.34%, azufre orgánico: 0.90% y azufre de sulfatos: 0.10%), bajo tres concentraciones de pulpa (9.09%, 16.67% y 23.08%). Los ensayos se compararon con otros bajo condiciones similares, pero utilizando medio T&K modificado. Todos los procesos se monitorearon con mediciones periódicas de hierro en solución, pH, potencial redox y concentración celular. El carbón fue analizado antes y después de la biodesulfurización por microscopía electrónica de barrido con analizador microquímico (SEM-EDX). Los ensayos con el medio de sales cloruros obtuvieron una oxidación del 70% de azufre pirítico después de 12 días para todas las concentraciones de pulpa evaluadas. En contraste, en los ensayos con el medio T&K modificado, la concentración de pulpa influyó en la oxidación de pirita y fue menor (por debajo de 55%).

A chloride salts medium was evaluated in biodesulfurization processes of a Colombian coal (2.34% total sulfur: 1.34% as pyritic, 0.90% as organic and 0.10% from sulfates), employing a consortium of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The process was carried out at three pulp concentrations (9.09%, 16.67% and 23.08%) and was compared with assays under similar conditions but containing modified T&K medium. All the tests were determined by measuring changes in soluble iron, pH, redox potential and microbial populations approach. Original and treated coal was analyzed by scanning electron microscopy with an energy-dispersive X-ray (SEM-EDX). For bioassays with chloride salts medium, the results showed above 70% of pyritic sulfur oxidation after 12 days, regardless of pulp concentration in contrast with results obtained for bioassays with a T&K modified medium where pulp concentration had influence and the pyrite oxidation was lower (below 55%).

A un carbón proveniente del municipio de Puerto Libertador, Córdoba-Colombia (2.34% de azufre total, con 1.34% pirítico, 0.90% orgánico y 0.10% de sulfatos), se le aplicó un cultivo mixto de Acidithiobacillus ferrooxidans y Acidithio bacillus thiooxidans, con el fin de evaluar procesos de biodesulfurización en suspensión, a partir de variables que influyen en el proceso: concentración inicial de hierro y pH de la solución lixiviante, bajo dos configuraciones de tamaño de partícula: pasante malla 8 (-malla 8) y pasante malla 60 (-malla 60), acorde con la serie Tyler de tamices. Los procesos de biodesulfurización se evaluaron cada dos días, mediante mediciones de la concentración de hierro, pH, potencial de óxido-reducción y crecimiento celular, en la solución. A partir de los ensayos realizados, se alcanzaron oxidaciones de azufre pirítico por encima del 50%, después de 12 días de proceso. Se pudo constatar que tanto el tipo de carbón tratado, como de las condiciones evaluadas, inciden en el grado de lixiviación alcanzado. La mejor eficiencia del proceso se observó al utilizar concentraciones de hierro iniciales menores a 1200 ppm y un pH inicial entre 1.5 y 1.3.

Biodesulfurization process for Colombian coal (2.34% total sulfur: 1.34% as pyritic, 0.90% as organic and 0.10% from sulfates) from municipality of Puerto Libertador (Córdoba, Colombia) was carried out. A mixed culture of A. ferrooxidans and A. thiooxidans was used. The study was mainly focused on the influence of pH, and iron concentration in coal leaching pro- cess. Two mineral particle sizes were evaluated: less 8 mesh (-malla 8) and less 60 mesh (-malla 60), Tyler series. Biodesulfurization processes were determined by measuring changes in soluble iron, pH, redox potential and microbial populations approach. The results showed above 50% of pyritic sulphur oxidation after 12 days. Coal type and evaluated conditions influence in leaching process. Less to 1200 ppm of iron concentration and initial pH between 1.5-1.3, were considered to have critical roles in optimizing pyrite dissolution.