There are few studies on the application of lactic acid bacteria in the reduction of anti-nutrient factors in paper mulberry silage. This study aimed to investigate the effects of different lactic acid bacteria on the fermentation quality and the amount of anti-nutritional factors in paper mulberry silage. Two strains of Lactobacillus plantarum (GX, isolated from paper mulberry silage; GZ, provided by Sichuan Gaofuji Biotechnology Co. Ltd.) were added as silage additives. On days 7, 15, 30 and 60 of the ensiling process, the fermentation quality, and the amount of anti-nutritional factors were measured. Compared with the control group, inoculation with Lactobacillus plantarum could rapidly reduce pH values, leading to lower NH₃-N/TN. Besides, it also significantly increased the lactic acid content (p < 0.05). The two strains of L. plantarum significantly reduced the content of hydrolysed tannin, condensed tannin, total tannin, oxalic acid, phytic acid and saponin (p < 0.05). Overall, this study found that the addition of lactic acid bacteria could significantly improve the fermentation quality of paper mulberry and reduce the amount of anti-nutrient factors (p < 0.05). Full article

The goal of this study was to evaluate the biodegradation of 1,4–dioxane using a mixed biological culture grown in textile wastewater sludge with 1,4–dioxane as the sole carbon source. The conditions for the long-term evaluation of 1,4–dioxane degradation were determined and optimized by batch scale analysis. Moreover, Monod’s model was used to determine the biomass decay rate and unknown parameters. The soluble chemical oxygen demand (sCOD) was used to determine the concentration of 1,4–dioxane in the batch test, and gas chromatography/mass spectrometry (GC/MS) was used to measure the concentrations via long-term wastewater analysis. Two types of reactors (continuous stirred reactor (CSTR) and plug flow reactor (PFR)) for the treatment of 1,4–dioxane from textile wastewater were operated for more than 120 days under optimized conditions. These used the mixed microbial culture grown in textile wastewater sludge and 1,4–dioxane as the sole carbon source. The results indicated efficient degradation of 1,4–dioxane by the mixed culture in the presence of a competitive inhibitor, with an increase in degradation time from 13.37 h to 55 h. A specific substrate utilization rate of 0.0096 mg 1,4–dioxane/mg MLVSS/h was observed at a hydraulic retention time of 20 h for 20 days of operation in a biomass concentration of 3000 mg/L produced by the mixed microbial culturing process. In the long-term analysis, effluent concentrations of 3 mg/L and <1 mg/L of 1,4–dioxane were observed for CSTR and PFR, respectively. The higher removal efficacy of PFR was due to the production of more MLVSS at 4000 mg/L compared to the outcome of 3000 mg/L in CSTR in a competitive environment. Full article

The present study describes the application of an acid tolerant and potentially probiotic L. paracasei SP3 strain, recently isolated from kefir grains, in the production of a novel functional beverage based on the fermentation of pomegranate juice. The fermentation ability of the novel strain was assessed during pomegranate juice fermentations at 30 °C for 24 h and storage at 4 °C for 4 weeks. Various parameters were assessed such as residual sugar, organic acid and alcohol levels, total phenolics content, antioxidant activity, astringency, cell viability, and consumer acceptance. Residual sugar was decreased by approximately 25%, while respectable amounts of lactic acid were determined (4.8 g/L) on the 28th day of storage, proving that the novel strain was effective at lactic acid fermentation. The concentration of ethanol was maintained at low levels (0.3–0.4 % v/v) and low levels of acetic acid were detected (0.6 g/L). The viability of L. paracasei SP3 cells retained high levels (>7 log cfu/mL), even by the 4th week. The total phenolic content (123.7–201.1 mg GAE/100 mL) and antioxidant activity (124.5–148.5 mgTE/100 mL) of fermented pomegranate juice were recorded at higher levels for all of the studied time periods compared to the non-fermented juice. The employment of the novel strain led to a significant reduction in the levels of hydrolysable tannins (42%) in the juice, reducing its astringency. The latter was further proven through sensorial tests, which reflected the amelioration of the sensorial features of the final product. It should be underlined that fruit juices as well as pomegranate juice comprised a very harsh food matrix for microorganisms to survive and ferment. Likewise, the L. paracasei SP3 strain showed a significant potential, because it was applied as a free culture, without the application of microencapsulation methods that are usually employed in these fermentations, leading to a product with possible functional properties and a high nutritive value. Full article

Riboflavin or vitamin B2 is a water-soluble vitamin and a precursor of flavin coenzymes, flavin mononucleotide, and flavin adenine dinucleotide, which play a key role as enzyme cofactors in energy metabolism. Candida famata yeast is a promising producer of riboflavin, as it belongs to the group of so-called flavinogenic yeasts, capable of riboflavin oversynthesis under conditions of iron starvation. The role of the particular structural genes in the limitation of riboflavin oversynthesis is not known. To study the impact of overexpression of the structural genes of riboflavin synthesis on riboflavin production, a set of plasmids containing genes RIB1, RIB6, and RIB7 in different combinations was constructed. The transformants of the wild-type strain of C. famata, as well as riboflavin overproducer, were obtained, and the synthesis of riboflavin was studied. It was found that overexpression of RIB1 and RIB6 genes coding for enzymes GTP cyclohydrolase II and 3,4-dihydroxy-2-butanone-4-phosphate synthase, which catalase the initial steps of riboflavin synthesis, elevated riboflavin production by 13–28% relative to the parental riboflavin-overproducing strains. Full article

Intercropping is a cropping strategy that makes efficient use of space, nutrients, and soil. A 2-year field trial was conducted in 2019 and 2020 to study the effects of different soybean sowing times (9 days before corn sowing (ST1), 0 days at corn sowing (ST2), and 9 days after corn sowing (ST3), respectively) and densities (120,000 plants ha⁻¹ (PD1), 150,000 plants ha⁻¹ (PD2), and 180,000 plants ha⁻¹ (PD3), respectively, and the planting density of corn was 60,000 plants ha⁻¹ constantly) on total yield and on mixed silage quality in corn-soybean strip intercropping system. The yield decreased with an increase in soybean planting density. Before ensiling, the total dry matter (DM) content increased with an increase in soybean planting density, while that of crude protein content decreased with sowing time. The interaction of planting density × sowing time was significant for neutral detergent fiber and water-soluble carbohydrate (WSC) content. After ensiling, the WSC content of PD2ST3 (4.90% DM) was the highest. The PD1 (4.51%) had a higher content of ammonia–nitrogen to total nitrogen than that of PD2 and PD3. The lactic acid content of PD2ST3 (3.14% DM) was the highest. In general, better silage quality and a higher total yield were obtained when soybean was sown at the planting density of 150,000 plants ha⁻¹ after 9 days of corn sowing. Full article

Volatile sulfur compounds (VSCs) are associated with unpleasant reductive aromas and are responsible for an important reduction in wine quality, causing major economic losses. Understanding the origin of these compounds in wine remains a challenge, as their formation and further evolution during winemaking can involve both chemical and biological reactions. Comparing the VSCs profile (i) of fermenting synthetic grape juices supplemented with a selected VSC (eight compounds tested) and incubated in presence or absence of yeast, and (ii) during storage of wines under an accelerated aging procedure, allowed us to elucidate the chemical and metabolic connections between VSCs during fermentation and aging. Yeast metabolism, through the Ehrlich pathway and acetylation reactions, makes an important contribution to the formation of compounds such as methionol, 3-methylthiopropionate, 3-methylthiopropylacetate, 3-mercaptopropanol, 2-mercaptoethanol and thioesters. By contrast, chemical reactions are responsible for interconversions between thiols and disulfides, the formation of thiols from thioesters or, more surprisingly, the formation of ethylthiopropanol from methionol during fermentation. During aging, variations in heavy VSC concentrations, such as an increase in 3-methylthiopropylacetate and a decrease in ethyl-3-methylthiopropionate formation, were evidenced. Overall, this study highlights that it is essential to consider both yeast metabolism and the high chemical reactivity of VSCs to understand their formation and evolution during winemaking. Full article

Oxygen is considered detrimental to anaerobic fermentation processes by many practitioners. However, deliberate oxygen sparging has been used successfully for decades to remove H₂S in anaerobic digestion (AD) systems. Moreover, microaeration techniques during AD have shown that small doses of oxygen may enhance process performance and promote the in situ degradation of recalcitrant compounds. However, existing oxygen dosing techniques are imprecise, which has led to inconsistent results between studies. At the same time, real-time oxygen fluxes cannot be reliably quantified due to the complexity of most bioreactor systems. Thus, there is a pressing need for robust monitoring and process control in applications where oxygen serves as an operating parameter or an experimental variable. This review summarizes and evaluates the available methodologies for oxygen measurement and dosing as they pertain to anaerobic microbiomes. The historical use of (micro-)aeration in anaerobic digestion and its potential role in other anaerobic fermentation processes are critiqued in detail. This critique also provides insights into the effects of oxygen on these microbiomes. Our assessment suggests that oxygen dosing, when implemented in a controlled and quantifiable manner, could serve as an effective tool for bioprocess engineers to further manipulate anaerobic microbiomes for either bioenergy or biochemical production. Full article

This paper reveals two of the challenges faced by Romania and proposes a sustainable and simple solution for its wine industry. First, substantial areas with vineyards that may produce qualitative wine, and second, the very low digitalization rate of industrial sectors. More precisely, this work proposes a solution for digitalizing the fermentation process of white wine, allowing it to be adapted for other control techniques (i.e., knowledge-based systems, intelligent control). Our method consists of implementing a pre-trained multi-layer perceptron neural network, using genetic algorithms capable of predicting the concentration of alcohol and the amount of substrate at a certain point in time that starts from the initial configuration of the fermentation process. The purpose of predicting these process features is to obtain information about status variables so that the process can be automatically driven. The main advantage of our application is to help experts reduce the time needed for making the relevant measurements and to increase the lifecycles of sensors in bioreactors. After comprehensive simulations using experimental data obtained from previous fermentation processes, we concluded that a configuration that is close to the optimal one, for which the prediction accuracy is high, is a neural network (NN) having an input layer with neurons for temperature, time, initial substrate concentration, and the biomass concentration, a hidden layer with 10 neurons, and an output layer with 2 neurons representing the alcohol and substrate concentration, respectively. The best results were obtained with a pre-trained NN, using a genetic algorithm (GA) with a population of 50 individuals for 20 generations, a crossover probability of 0.9, and a probability of mutation of 0.5 that uniformly decreases depending on the generations, based on a beta coefficient of 0.3 and an elitist selection method. In the case of a data set with a larger number of variables, which also contains data regarding pH and CO₂, the prediction accuracy is even higher, leading to the conclusion that a larger data set positively influences the performance of the neural network. Furthermore, methods based on artificial intelligence applications like neural networks, along with various heuristic optimization methods such as genetic algorithms, are essential if hardware sensors cannot be used, or if direct measurements cannot be made. Full article

The aim of this study was to evaluate the microbial changes and biogenic amine (BA) formation in rapeseed meal (RP) during fermentation with a bacterial starter combination of Lactiplantibacillus plantarum-LUHS122 and -LUHS135, Lacticaseibacillus casei-LUHS210, Lentilactobacillus farraginis-LUHS206, Pediococcus acidilactici-LUHS29, and Liquorilactobacillus uvarum-LUHS245. Sampling was carried out after 12 h and 7, 14, 21, and 28 days of cultivation under conditions of constant changes to the substrate, with a change frequency of 12 h. The highest lactic acid bacteria (LAB) and yeast/mould counts were established in RP fermented for 14 days (8.29 and 4.34 log₁₀ CFU/g, respectively); however, the lowest total enterobacteria count was found in RP fermented for 12 h (3.52 log₁₀ CFU/g). Further metagenomic analysis showed that Lactobacillus spp. were the most prevalent species in fermented RP. The changes in microbial community in RP led to differences in BA formation. Putrescine and phenylethylamine were found in all fermented RP samples, while the contents of some other amines increased with prolonged fermentation. Finally, the use of combined fermentation could ensure Lactobacillus spp. domination; however, other parameters should be controlled due to the formation of undesirable compounds. Full article