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The cob is the residue generated from the separation of the grain from the cob, and due to its components, it is considered a lignocellulosic material, so its use is limited, which favors the burning of the cob and its spreading, thus generating a problem of environmental pollution. Probiotics are live microorganisms that, when supplied in adequate...
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Context 1
... 3 shows the behavior of substrate consumption using the Hom model. According to the graph, using 10% inoculum, the curve is closer to the slope, so there is a better fit for the model; this is verified with R 2 shown in Table 2, whose value is higher as well as the value k (0.02534), a compared 15% and the value of m (0.7609) the smallest whose case is that at lower values of m, the affinity of the bacteria for the substrate is greater, so that when using the 10% inoculum, the bacteria adapts to the substrate and therefore carry out the process of biotransformation of the waste , using the anaerobic fermentation strategy. It is worth mentioning that when using the 10% dose, the percentage of carbohydrate removal was 52.15%, while in the experiment in which 15% of inoculum was added, 40.79% of the carbohydrates were removed. ...Context 2
... Figure 4 it can see the corn cob residue before ( Figure 4A) and after ( Figure 4B) performing the anaerobic fermentation. Table 2 shows the kinetic parameters obtained from the anaerobic fermentation using Lactobacillus acidophilus bacteria with the two inoculum concentrations that were used for the experiments, highlighting that when using 10% of inoculum, the bacteria adapts to the substrate more quickly, allowing the biotransformation of waste into products such as biomass and lactic acid. ...Citations
In the present study, the anaerobic biotransformation process of craft brewers’ spent grains (CBSG) was evaluated using two
strains of lactic acid bacteria (LAB), Lactobacillus casei and Bacillus subtilis, as well as their efect on rheological properties
at the end of the process. Three doses of inoculum were applied (5, 10, and 15% v v−1) with three replications at constant
temperature and pH (37±0.5 °C, 6.5); the process was monitored every 4 h for 72 h to determine carbohydrate consumption
and cell growth. At the beginning and end of the process, the substrate was rheologically characterized to observe physical
changes during the process of biotransformation, especially in terms of viscosity, shear stress, and rheological parameters (k,
n). The results showed that the substrate exhibited dilating behavior (n>1) prior to fermentation. At the end of the process,
the same fow behavior was observed in the substrate; however, there was a thinning of the fuid due to the action of probiotic
bacteria when degrading lignocellulosic compounds and in turn by cell growth, which resulted in the production of probiotic
biomass, of which the species B. subtilis produced the highest content of total nitrogen (TN) and proteins with 4.10% and
25.62% respectively (p<0.05). This represents an increase of 126% of TN and proteins with respect to their initial contents
(1.80% and 11.29%, respectively). In this way, it was possible to evaluate the nutrient content of CBSG and to correlate the
rheological parameters during the development of the process as an efcient control strategy, establishing regions of change
in the fnal values of the variables, such as viscosity, shear stress, consistency index, and fow index, at the end of the process.
Brewers' spent grains (BSGs) are the most abundant waste generated from the craft brewing process, accounting for approximately 85% of the total byproduct obtained. The need to develop beneficial alternatives for the contribution of the industrial sector and sustainable development has increased interest in the fermentation processes used to produce biomass, using probiotic microorganisms that provide health benefits for those who consume it, obtaining byproducts rich in nutrients. Therefore, this research aimed to evaluate the growth of Lactobacillus casei in Mar, Rogosa and Sharpe broth (MRS) and to evaluate the feasibility of growing L. casei in craft beer residues. To achieve this goal, a 10% v/v inoculum of probiotic bacteria was used in both media. The process consisted of monitoring the biotransformation process at 37°C and 120 rpm for 72 hours and evaluating carbohydrate consumption and cell growth. At the end of 52 h, the carbohydrate concentration in combination with BSG was completely consumed, considering that the initial value was 16.49 g/L. In the case of the MRS medium, a value of 3.42 g/L was obtained at 72 h. Regarding the pH range with the MRS broth and with BSG, the values were 6.89-5.43 and 5-4.41, respectively. Due to the acidity of the synthetic medium, the pH of the synthetic medium was greater than that of BSG. However, L. casei managed to develop in a similar way since quite similar cell growth values were obtained in both media, so it is feasible to use BSG as a culture medium for the development of probiotic species.
Lactic acid (LA) and probiotic biomass production were evaluated from bovine manure supported with 12% v/v molasses using
three probiotic bacteria, Lactobacillus acidophilus, Lactobacillus fermentum, and Bacillus subtilis, with three inoculum concentrations, 5%,
10%, and 15% v/v. Laboratory-scale tests were carried out in 250-mL flasks (useful volume of 200 mL) at 37°C and 120 rpm for 72 h. During
this time, samples were taken every 4 h to determine (1) the LA content using titration, (2) cell growth using the poured plate method, and
(3) consumption of carbohydrates using the anthrone-sulfuric method. The data obtained were adjusted to the Gompertz generalized four�parameter model to obtain the kinetic parameters of the growth of the bacteria in the residue. With the species L. acidophilus at 10% v/v, the
highest LA production yield was obtained, YðP=SÞ ¼ 0.7 g LA=g carbohydrates, with a concentration of 13.5 g LA=L (p > 0.05) and values
of μmax ¼ 0.161=h and Ks ¼ 0.46 g=L. With the same bacteria at 15% v/v, the biomass obtained had the highest concentration of proteins,
32.19% dry weight of proteins (p > 0.05). The results showed that bovine manure has the potential to produce LA and biomass, which are
products with high nutritional, economic, and energetic value.
The massive generation of pig manure significantly contributes to the emission of greenhouse gases; in addition, its poor disposal represents a serious risk to human and animal health. In recent years, the microbial fermentation process has become relevant because it is considered a circular bioeconomy strategy, guaranteeing the recovery of agro-industrial waste and waste management. In this work, the production of lactic acid and biomass was evaluated from an anaerobic bioconversion process of swine residues in the presence of L. acidophilus. A 5 L capacity reactor was used, and different stirring speeds were evaluated (100, 150, and 200 rpm). It was concluded that the highest production of lactic acid and biomass was 30.15 and
, respectively, which were reached during the experiments carried out at 100 rpm. The biomass was analyzed to determine the content of carbohydrates, proteins, and cell count, which were
, 17.16%, and
, respectively. Finally, the fuzzy logic technique was applied, and response surface graphs were generated to determine the variables with the greatest impact on lactic acid and biomass generation.
Agro-sugarcane waste (ASW) is generated during the manual harvest of sugarcane and burning, which represents an environmental issue because greenhouse gases are generated, and they are not treated correctly but represent a rich source of nutrients to obtain valuable biological products of economic and environmental interest. However, there are few works that have reported information on the growth kinetics of the process to obtain subproducts and their advantages. The aim of this study was to determine the growth kinetics of Lactobacillus acidophilus during the anaerobic bioconversion process of ASW, which was carried out in a laboratory-scale stainless steel reactor with a capacity of 5 L at different agitation speeds of 100, 150, and 200 rpm at 37 °C for 72 h, and kinetics parameters were obtained by Gompertz, Gompertz generalized, and logistic models. Considering an initial carbohydrate concentration of 58.46 g L⁻¹, at 100 rpm, a μmax of 0.22 h⁻¹ was calculated, and 54.16 g LA L⁻¹ (0.87 g LA g carbohydrates⁻¹) and 154.65 g biomass L⁻¹ were produced. The kinetics parameter values for the anaerobic biotransformation process of sugarcane residues let us propose operation conditions to maximize LA and biomass production and represent an attractive strategy to obtain high value-added products in both phases of the final product, which is obtained without greenhouse gas production.
This study evaluated the rheological behavior of the pig waste biotransformation process to produce lactic acid (LA) and biomass with Lactobacillusacidophilus in a stirred reactor. In addition, cell growth, carbohydrate consumption, and LA production were measured at three different agitation speeds, 100, 150, and 200 rpm at 37 °C, with a reaction time of 52 h. During the development of the process, the kinetic and rheological parameters were obtained using the logistic, Gompertz, generalized Gompertz, Ostwald de Waele, and Herschel–Bulkley mathematical models, respectively. The substrate used was pig manure, to which molasses was added at 12% v/v to increase the concentration of carbohydrates. The results suggest that mass exchange is favorable at low agitation speeds. Nevertheless, the presence of molasses rich in carbohydrates as a carbon source modifies the characteristics of the fluid, dilatant (n > 1) at the beginning of the process to end up as pseudoplastic (n < 1) due to the addition of exopolysaccharides and the modification of the physical structure of the substrate. This effect was confirmed by the Herschel–Bulkley model, which presented a better fit to the data obtained, in addition to finding a direct relationship between viscosity and pH that can be used as variables for the control of bioconversion processes of pig manure into biomass rich in Lactobacillus acidophilus.
