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Wheat straw is a highly abundant waste material that can be utilized as a carbon source in various fermentation processes. This study aimed to generate citric acid using Aspergillus niger from wheat straw and to evaluate its preservative potential in fresh poultry meat samples. Wheat straw samples were dried, pulverized, and chemically pretreated. The obtained wheat straw slurry (100 g L-1) was saccharified at 50 °C using cellulases obtained from Trichoderma viride. The hydrolyzed substrate was then subjected to fermentation by Aspergillus niger at 35 °C, 180 rpm, and pH=5 for 7 days. The citric acid generated was determined via the HPLC technique. Poultry meat was obtained and treated by soaking in different concentrations (1, 2, and 3%) of citric acid (n=4). The treated samples were then stored in sterile plastic bags for 14 days at 4 °C. Total Bacterial Count (TBC), Total Coliform Count (TCC), TVB-N, and TBARS were determined as storage progressed, and pH, TTA, and sensory evaluation were carried out. The highest citric acid obtained was 14.15 g L-1 which resulted in a percent yield of 26.18%. Treatment of meat with 3% citric acid had the lowest TBC and TCC of 2.55 and 0.34 Log10 CFU g-1 after 7 days of storage respectively. There were significant differences in the TBC and TCC observed within the treatments (P<0.05) as observed. T-VBN and TBARS reduction during storage was most evident in meat samples treated with 3% citric acid, retaining acceptability of 31.22 mg 100 g-1 and 0.74 mg kg-1, respectively at day 10. The 2% citric acid treatment had the best sensory attributes (16) on day 7. Findings from this study show that treatment with 2% citric acid and above showed promising results in extending the shelf-life of fresh poultry meat samples. [ABSTRACT FROM AUTHOR]

The standardization of cultivation processes that allow high levels of conidia growth and formation is required to formulate Trichoderma products to combat fungal diseases in agronomically important crops. This study evaluated the effects of inoculation using different inoculum concentrations (1.0x105, 1.0x106, and 1.0x107 conidia mL-1) and inoculum volumes (10, 30, and 50 mL). Later, it evaluated the effect of adding microelements (CaCO3, KH2PO4, MgSO4*7H2O, and (NH4)2SO4) on the conidiogenesis of two strains of Trichoderma asperellum (GRB-HA01 and GRB-HA02) in solidstate and liquid fermentation processes. After 12 days of fermentation, the highest conidiogenesis values for Trichoderma asperellum GRB-HA01 (6.9x109±5.7x10² conidia g-1) and Trichoderma asperellum GRB-HA02 (1.3x109±1.4x10² conidia g-1) were achieved using an inoculum volume of 10 mL at a concentration of 1.0x07 conidia mL-1. Adding CaCO3 (1 g g-1), resulted in the highest conidia concentrations for Trichoderma asperellum GRB-HA01 (3.0x1011±2.5x10² conidia g-1) and Trichoderma asperellum GRB-HA02 (8.6x1010±1.1x10¹ conidia g-1), reducing fermentation times to 9 days. The conidiogenesis obtained with liquid fermentation was lower and affected Trichoderma asperellum GRB-HA01 (3.1x107±1.1x10² conidia g-1) and Trichoderma asperellum GRB-HA02 (3.1x109±2.8x10² conidia g-1). This study showed that inoculation and adding microelements were important factors in the conidiogenesis processes of Trichoderma asperellum GRB-HA01 and GRB-HA02. Additionally, it was evidenced that solid-state fermentations are more efficient than liquid fermentation processes. [ABSTRACT FROM AUTHOR]

Unstructured models for cell growth, xylose consumption and xylitol production were applied for to describe the fermentation kinetics of xylitol production using Candida tropicalis in synthetic medium, and in non-detoxified oil palm empty fruit bunch (OPEFB) hydrolysate at 100 mL flask scale. In synthetic medium, the experimental maximum specific growth rate (µmax) and the cell mass yield factor (YX/S) were closer to the results of the Tessier model than those of the Contois and Monod models. Whereas, in non-detoxified OPEFB hydrolyzate, these parameters were closer to the results of the Contois model than those of the Tessier and Monod models. According to the models' results, xylitol is mainly produced during the cell growth phase. The Tessier model in synthetic medium and Contois model in non-detoxified OPEFB hydrolysate had a coefficient of variation in growth kinetics of 32 and 33%, respectively. The significance of this study lies in simplifying the fermentation process through a an unstructured and non-segregated model using three events at the same time, cell growth, substrate consumption and metabolite production. [ABSTRACT FROM AUTHOR]

Brewer's Spent Grain (BSG) is renewable lignocellulosic biomass generated from the beer brewing process. It serves as a substrate for various biotechnological applications. BSG was used as the main substrate for bioethanol production with Saccharomyces carlsbergensis in submerged fermentation. Saccharification and fermentation studies were performed for the production of bioethanol. A sterilized fermenter was loaded with 50 g L-1 of BSG at 29±2 °C and an agitation speed of 180 rpm. pH was adjusted to 6.0 before the addition of 500 mL of yeast culture for 7 days under submerged and optimized conditions. The fermented product was concentrated using a rotary evaporator at 66±1 °C, and ethanol was qualitatively determined by the dichromate method. Bioethanol yield was 22%, with a specific gravity of 0.8 at 28 °C. Fourier-Transform Infrared Spectroscopy (FTIR) confirmed the presence of -CH3 stretch, -OH stretch and -CH2stretch in bioethanol. For the preservative test, Staphylococcus spp., Erwinia spp., Lactobacillus spp., Bacillus spp., Xanthomonas spp., Pseudomonas spp., Micrococcus spp. and Corynebacterium spp. were the bacteria isolated from fruits examined from different regions of Osun State. The genera of fungi isolated were Aspergillus, Colletotrichum, Penicillium, Fusarium, Alternaria, Rhizopus, Candida, Saccharomyces, Geotrichium and Pichia. Bioethanol produced from BSG inhibited the growth of microorganisms with zones of inhibition range from 7.0 mm to 11.5 mm, and thus, selected fruits were preserved. Hence, the fermentation technology of agro-industrial wastes with microorganisms can be adopted to convert waste biomass to useful resources. [ABSTRACT FROM AUTHOR]

In the present investigation, the effects of the substrate composition, organic load, medium acidification time, operation pH, and temperature on the production of hydrogen by anaerobic fermentation with fruits and vegetable waste, and fresh mucilage of coffee was evaluated. For this purpose, tests were carried out in a 20-liter bioreactor operated in batch mode, under a central composite experimental design (CCD). The fermentations were conducted under mesophilic conditions, without adding inoculum, and without sterilizing the substrate. The results for maximum daily hydrogen production (MDP), the maximum hydrogen content in the gas (MHC) and cumulative production (CHP) showed an acceptable fit to second-order polynomial models. All the independent variables were significant, especially the operation pH and the acidification time. Also, the premises for a model obtained by regression, according to error analysis, were fulfilled. In the same way, it was possible to optimize the response variables. The maximum specific production concerning the organic load was 5511 mL H2gCODremoved-1, and regarding the volatile solids was of 670 mL H2gVSadded-1. These values are higher than those reported with similar substrates in continuous fermentation, with cell retention, use of inoculum, and substrate pretreatment. [ABSTRACT FROM AUTHOR]

Organic waste is considered a substrate of great interest to produce biohydrogen. In the present work, the influence of some physical and chemical parameters in the operation of a bioreactor for biohydrogen generation were studied, taking as a substrate organic residue from a wholesale food market without adding inoculum. Therefore, an experimental design of central composition was made, with four factors and two levels. The dependent variables were maximum hydrogen content (% of H2), daily production of hydrogen (L H2 d-1) and its cumulative production (L H2). The independent variables were operation pH (pHo), pH of acidification (pHa), the duration time of the acidification stage, and stirring. A numerical optimization was carried out, allowing the prioritization of the factors, and maximizing the response variables. Resulting in a yield of up to 14.9 L H2 d-1, a hydrogen content of 49.2% and a cumulative production of 21.6 L H2, for pHa values of 4.9; pHo between 6 and 6.1; acidification time of 2 d and stirring of 41.4 rpm. Likewise, a graphical optimization was carried out, reaching 14.9 L H2 d-1, a hydrogen content of 44.2% and an accumulated 22.8 L H2, for pHa values between 4.5 and 4.95; pHo between 5.6 and 6.3; acidification time of 2 d, and stirring of 37.1 rpm. Maximum yields were 1.9 L H2 Lwaste.day-1, 4800 mL H2 gCOD-1, and 608.6 m L H2 gTVSadded-1, values similar to those reported by other authors using organic waste in the production of hydrogen, using inoculum. [ABSTRACT FROM AUTHOR]

El lactosuero de quesería es un subproducto líquido obtenido después de la precipitación de la caseína durante la elaboración del queso. Contiene principalmente lactosa, proteínas como sustancias de importante valor nutritivo, minerales, vitaminas y grasa. La composición y tipo de lactosuero varía considerablemente dependiendo del tipo de leche, tipo de queso elaborado y el proceso de tecnología empleado. La lactosa es el principal componente nutritivo (4,5 % p-v), proteína (0,8% p/v), y lípidos (0,5%). Si en la coagulación de la leche se utiliza enzimas el lactosuero se denomina dulce, y si se reemplaza la enzima por ácidos orgánicos se denomina ácido. Para la industria alimentaria, el lactosuero constituye una fuente económica de proteínas que otorga múltiples propiedades en una amplia gama de alimentos. Los productos del suero, incluyendo la lactosa, mejoran la textura, realzan el sabor y color, emulsifican y estabilizan, mejoran las propiedades de flujo y muestran muchas otras propiedades funcionales que aumentan la calidad de los productos alimenticios. Basados en el valor nutricional del lactosuero, un número de usos comerciales se han obtenido como etanol, ácidos orgánicos, bebidas no alcohólicas, bebidas fermentadas, biomasa, concentrados, aislados e hidrolizados de proteína, películas comestibles, medio de soporte para encapsular sustancias, producción de xantana, enzimas, separación de la lactosa para fines endulzantes en alimentos entre otras aplicaciones.Cheese whey is a by-product liquid obtained after precipitation of casein during the production cheese. Mainly contains lactose, protein and important nutritional substances, minerals, vitamins and fat. The type and composition of whey varies considerably depending on the type of milk, cheese produced and the process technology used. Lactose is the primary nutritional component (4.5% pv), protein (0.8% w / v) and lipids (0.5%). If the milk clotting enzyme used is called sweet whey, and if the enzyme is replaced by organic acids is called acid. For the food industry, whey is an economic source of protein that gives multiple properties in a wide range of foods. Whey products, including lactose, improve texture, enhance the flavor and color, emulsified and stabilized, improved flow properties and exhibit many other properties that enhance the quality of foodstuffs. Based on the nutritional value of whey and a number of commercial uses have been obtained as ethanol, organic acids, non-alcoholic drinks, fermented beverages, biomass, concentrates, isolates and hydrolysates of protein, edible films, means of support to encapsulating substances, xanthan production, enzymes, separation of lactose for sweeteners in food among other applications.

En el presente artículo se hablara del proceso de fermentación del cacao, pero antes de entrar a detallar este proceso, es conveniente dar algunas anotaciones sobre los sistemas de recolección o “cosecha” empleados en distintos lugares, pues ellos tienen sus diferencias y en ocasiones no se efectúan con todo el cuidado necesario tanto para el árbol como para el producto que irá a los depósitos de fermentación.