Fermentation Rate Research Articles

Focus on Co-digestion of waste activated sludge and food waste via yeast pre-fermentation and biochar supplementation: The optimization and mechanism

Anaerobic digestion is a promising method to recover energy from waste, but the slow rate of fermentation hinders its application. Yeast pre-fermentation has been reported to enhance organic matter solubilization and ethanol production to promote syntrophic metabolism and methanogenesis. However, the pre-fermentation with yeast has not been optimized so far. In this study, the lab-scale experiment was conducted to optimize operational conditions, and a pilot-scale study was conducted to evaluate the combined strategy of yeast pre-fermentation and biochar supplementation. Results demonstrated that at a fermentation time of 6 h, temperature of 30 °C, and dry yeast dosage of 2‰, the highest ethanol production was achieved, which accounted for 6.2% of the total COD of pre-fermentation effluent of a mixture of waste-activated sludge and food waste. The methane yield of the pre-fermented waste averaged 161.3 mL/g VS/d, which was 18.7% higher than that of the control group without the yeast inoculation (135.8 mL/g VS/d). With supplementing biochar of 0.5 and 1 g/L, the average methane production was 27.8% and 36.4% higher than the control group, respectively. The volatile solid removal rate was over 10% higher than the control (58.2 ± 3.12%). Consistently, the electrochemical properties of sludge with biochar were significantly improved. A pilot-scale experiment further showed that the methane production with the yeast pre-fermentation and biochar supplementation reached 227 mL/g VS/d, 54.3% higher than that without yeast pre-fermentation and biochar. This study provided a feasible method to combine yeast pre-fermentation and biochar supplementation under optimal conditions, which effectively increased methane production during anaerobic digestion of organic waste.

Physical Contact between Torulaspora delbrueckii and Saccharomyces cerevisiae Alters Cell Growth and Molecular Interactions in Grape Must

The use of multi-starters in oenological conditions (Saccharomyces cerevisiae and non-Saccharomyces species) is becoming increasingly common. For the past ten years, the combination of Torulaspora delbrueckii and S. cerevisiae has been proposed to winemakers to improve the wine aromatic profile compared to pure inoculation with Saccharomyces cerevisiae. In this work, two commercial strains, T. delbrueckii Zymaflore® Alpha and S. cerevisiae Zymaflore® X5 (Laffort compagny, Floirac, France), were investigated in Sauvignon blanc must using a fermentor with a double compartment allowing for physical separation of the two yeast species. The physical separation of the two species resulted in significant differences in the growth, fermentation kinetics (maximum fermentation rate (+13%)), fermentation duration (−14%) and the production of 3SH (+35%) in comparison to mixed cultures with contact. Proteomic analysis confirmed cell–cell contact interactions, as strong differences were observed for both species between mixed cultures with and without physical contact. T. delbrueckii mortality in mixed cultures with physical contact may be explained by an oxidative stress. Indeed two proteins implicated in the oxidative stress response were found in significantly higher amounts: a cytosolic catalase T and a cytoplasmic thioredoxin isoenzyme. For S. cerevisiae, an increase in proteins involved in the respiratory chain and proton transport were found in higher amounts in pure cultures and mixed culture without physical contact. Our results confirmed that the two mixed inoculations increased certain minor esters (ethylpropanoate, ethyl dihydrocinnamate and ethyl isobutanoate) specifically produced by T. delbrueckii, 3.4-fold more compared to in the pure S. cerevisiae culture. In conclusion, these results provide new insights into the underlying mechanisms involved in cell–cell contact and confirm the benefits of using T. delbrueckii species under winemaking conditions.

Optimization of the Fermentation Conditions of Huaniu Apple Cider and Quantification of Volatile Compounds Using HS-SPME-GC/MS.

The fermentation process and composition of volatile compounds play a crucial role in the production of Huaniu apple cider. This study aimed to optimize the fermentation conditions of Huaniu apple cider and quantify its volatile compounds using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS). The optimal fermentation parameters were determined using response surface methodology (RSM). The optimal fermentation temperature was 25.48 °C, initial soluble solids were 18.90 degrees Brix, inoculation amount was 8.23%, and initial pH was 3.93. The fermentation rate was determined to be 3.0, and the predicted value from the verification test was 3.014. This finding demonstrated the excellent predictability of a RSM-optimized fermentation test for Huaniu apple cider, indicating the reliability of the process conditions. Moreover, the analysis of volatile compounds in the optimized Huaniu cider identified 72 different ingredients, including 41 esters, 16 alcohols, 6 acids, and 9 other substances. Notably, the esters exhibited high levels of ethyl acetate, ethyl octanoate, and ethyl capricate. Similarly, the alcohols demonstrated higher levels of 3-methyl-1-butanol, phenethylethanol, and 2-methyl-1-propanol, while the acids displayed increased concentrations of acetic acid, caproic acid, and caprylic acid. This study provides the essential technical parameters required for the preparation of Huaniu apple cider while also serving as a valuable reference for investigating its distinct flavor profile.

Overcoming extended lag phase on optically pure lactic acid production from pretreated softwood solids.

Optically pure lactic acid (LA) is needed in PLA (poly-lactic acid) production to build a crystalline structure with a higher melting point of the biopolymer than that of the racemic mixture. Lignocellulosic biomass can be used as raw material for LA production, in a non-food biorefinery concept. In the present study, genetically engineered P. acidilactici ZP26 was cultivated in a simultaneous saccharification and fermentation (SSF) process using steam pretreated softwood solids as a carbon source to produce optically pure D-LA. Given the low concentrations of identifiable inhibitory compounds from sugar and lignin degradation, the fermentation rate was expected to follow the rate of enzymatic hydrolysis. However, added pretreated solids (7% on weight (w/w) of water-insoluble solids [WIS]) significantly and immediately affected the process performance, which resulted in a long lag phase (more than 40h) before the onset of the exponential phase of the fermentation. This unexpected delay was also observed without the addition of enzymes in the SSF and in a model fermentation with glucose and pretreated solids without added enzymes. Experiments showed that it was possible to overcome the extended lag phase in the presence of pretreated softwood solids by allowing the microorganism to initiate its exponential phase in synthetic medium, and subsequently adding the softwood solids and enzymatic blend to proceed to an SSF with D-LA production.

Impact of ultrasound-assisted fermentation on buffalo yogurt production: Effect on fermentation kinetic and on physicochemical, rheological, and structural characteristics

This work evaluated the buffalo milk acidification kinetics using partially or fully ultrasound-assisted fermentation and yogurt characteristics without or with sugar (5%). The results showed that assisted fermentation in an ultrasonic bath (25 kHz, 38 W/L) accelerates the fermentation rate (up to 41% increase), reducing the fermentation time (up to 2 h), and, in some conditions, improved the yogurt quality. Samples produced by US-assisted fermentation under 1 or 2 h had higher water holding capacity (up to 35%), consistency index (up to 423%), and apparent viscosity (up to 246%), explained by the formation of a stronger gel, as elucidated by microscopy images. In contrast, no differences in pH, acidity, and lactic acid bacteria viability were observed. Additionally, sucrose contributed positively to the yogurt quality, improving gel formation. Therefore, buffalo milk fermentation under US (up to 2 h) is an interesting strategy that accelerates fermentation and improves the buffalo yogurt quality.

In-depth exploration on the effects of organic nitrogen addition during different fermentation periods on the quality of cider

Nitrogen is an essential element for the growth and metabolism of Saccharomyces cerevisiae, and has a great impact on the quality of cider. In this study, the effects of organic nitrogen addition at different stages of fermentation process on the quality of cider were systematically explored. The main projects included the analysis of fermentation rate, yeast growth, organic acids, amino acids, and volatile aroma compounds. The results indicated that organic nitrogen addition speeded up fermentation rate and shortened fermentation time. The organic nitrogen addition before fermentation and at the early stationary phase altered the composition of organic acids in cider. Moreover, with the addition of organic nitrogen at three stages of fermentation (pre-fermentation, logarithmic and stable phases of yeast growth), the total concentrations of volatile aroma substances in ciders were 10.57 mg/L, 11.97 mg/L and 11.05 mg/L respectively, which were all significantly higher than that in control group (9.69 mg/L). A close relationship between free amino acids consumed during fermentation and volatile aroma compounds produced was revealed by partial least-squares regression analysis. Overall, this study provided a new strategy for cider quality improvement by evaluating the effects of organic nitrogen on the aroma composition of cider.

Fermentation characteristics of different sources of dietary fiber in vitro and impacts on growth performance, nutrient digestibility and blood para-meters of piglets

This study aimed to assess the effect of various source of high-fiber ingredients on growth performance, apparent digestibility of nutrients, and blood para- meters of piglets by investigating their in vitro fermentation characteristics. A total of 300 healthy crossbred piglets were randomly allocated to one of five diets including corn-soybean meal basal diet (CON), sugar beet pulp (SBP), soybean hull (SBH), fermented distillers’ grains (FDG), and kelp powder (KP). In vitro fermentation analysis revealed that the predominant short-chain fatty acids produced were acetate and valerate. Sugar beet pulp and kelp powder exhibited rapid fermentation rates, in contrast to SBH, oat bran, and FDG. The apparent total tract digestibility of dry matter (P < 0.05), gross energy (P < 0.05), and crude protein were decreased (P < 0.001) in different fiber diets than the CON diet. The serum concentration of threonine was increased by feeding fibers diets (P < 0.05). In conclusion, a diet containing 3% SBP (with a soluble-to-insoluble dietary fiber ratio of 17.04%) showed the best effects on increasing nutrients digestibility and serum amino acid concentrations. These findings may inform future applications of SBP in piglet nutrition.

Efficient Biofuel Generation of Plants via Enzymes

The purpose of this research is to observe the Efficiency of Biofuel Generation of Plants Using Enzymes. The question being asked is at which concentration of glucose will yeast fermentation rates be the most efficient in order to produce Ethanol through fermentation? It was predicted glucose concentrations and ethanol production rates would increase simultaneously. Ethanol is a renewable transportation fuel made from plants. Methods for researching this topic includes studying the environmental impacts of Ethanol, how it is produced, the process of enzyme digestion, the differences between cellulose and cellulase and the process of yeast alcohol fermentation. The methodology required for this experiment includes creating eight samples: Cellulase + Yeast, Cellulose + Yeast, Cellulase + Cellulose + Yeast, Cellulase + Cellulose + No yeast, and all four concentrations of glucose in separate samples (0.5%, 1%, 3% and 5%). The apparatus used to collect the data is made up of a syringe attached to a pipette, each sample started at a given volume of mL then as the samples began fermenting and releasing CO2 data was recorded for 15 minutes in 1 minute intervals.The volume of carbon dioxide released corresponds to the amount of sugar (glucose) fermented. The results of this experiment show a correlation between the increased rate of ethanol production as glucose concentrations increase. The interaction between cellulose and cellulase demonstrate the process of producing glucose through enzyme digestion.

Effects of sheep breed and grass silage quality on voluntary feed intake and enteric methane emissions in adult dry ewes

Forty adult dry ewes in early pregnancy participated in a 2 × 2 factorial design study to investigate the effects of two grass silage qualities (Early vs. Average; 7.12 vs 5.74 MJ of net energy lactation per kg dry matter (DM)) and two breeds (Norwegian White Sheep, NWS; Old Norwegian Spæl, ONS) on voluntary feed intake and enteric methane (CH4) emissions. Ewes of the two breeds were equally mixed in two groups and assigned to Early and Average silage quality for first part of the experiment and switched for the second part of the experiment. Each period of the experiment lasted for three weeks; one week of adaptation and two weeks of measurements. The ewes were housed in individual pens and fed silage ad libitum. Feed intake was continuously logged using the BioControl System. Enteric CH4 was measured for 10 weekdays in Portable Accumulation Chambers in each period. Average body weight (BW) for NWS and ONS were 91 and 60 kg, respectively. ONS had significantly (p < 0.0001) lower daily DM intake (DMI), DMI/kg BW, daily NDF intake, NDF/kg BW, g CH4/day and g CH4/kg BW, compared to the NWS. The Early grass silage (p < 0.0001) resulted in higher daily DMI (kg DMI/day, kg DMI/kg BW), and higher enteric CH4 emissions/kg BW when offered to the ewes, compared to the Average grass silage. Significant interactions (p < 0.05) between breed and grass silage quality were observed for both measures of feed intake and CH4 emission. The results show that breed differences in CH4 emission is strongly linked to DMI, however breed differences were still present after correcting for DMI, which indicated breed differences not explained by BW or DMI. Persistent breed differences after correcting for DMI may be related to contrasts in rumen passage rate, NDF digestibility, rumen microbiome, fermentation rate etc. We conclude that improved grass silage quality may be a potential mitigation option. However, to avoid weight gain in early pregnancy in an ad libitum feeding regime, the practical applicability may be limited to periods with higher feed requirements, such as in late pregnancy and early lactation. The breed differences in enteric CH4 emission need to be related to productivity (e.g., fecundity, lamb growth rate). Potential breed differences not explained by body size and/or DMI need to be further investigated.

In vitro fermentation characteristics of fruit and vegetable juicing wastes using human fecal inoculum are determined by cell wall architecture

Fruit and vegetable juicing wastes are a promising source of hydrocolloids with potential gut fermentation benefits for applications in foods. The aim of this study was to investigate the fermentation characteristics of juicing wastes from apple, beetroot, carrot, celery, orange and pineapple to characterise fermentation rates, gas production and end-products. All juicing wastes had high dietary fibre content (70–90%) and high water-holding capacity (9–12 g H2O per gram dry matter) consistent with food application potential but had diverse fermentation rates and extents over a 48h period. Apple, carrot and orange waste were well-fermented, beetroot and celery waste were less well fermented and pineapple waste was the least fermented as indicated by gas production and short chain fatty acid concentrations. Variations in fermentability were determined by cell wall architecture more than polymer chemistry. Apple, carrot and orange waste were primarily parenchymal fleshy tissue with loosely packed cell walls and readily fermentable. Beetroot and celery waste had more compact cell walls, while pineapple waste had the most densely packed cell walls and the highest cellulose content. The molecular composition of unfermented material also changed during fermentation, with pectin the fastest fermenting, followed by hemicelluloses such as (arabino)xylan, xyloglucan, and mannan while cellulose was the slowest. The results show the potential for unrefined juicing wastes to provide sustained fermentation throughout the large intestine.

Sour Beer as Bioreservoir of Novel Craft Ale Yeast Cultures.

The increasing demand for craft beer is driving the search for novel ale yeast cultures from brewing-related wild environments. The focus of bioprospecting for craft cultures is to identify feral yeasts suitable to imprint unique sensorial attributes onto the final product. Here, we integrated phylogenetic, genotypic, genetic, and metabolomic techniques to demonstrate that sour beer during aging in wooden barrels is a source of suitable craft ale yeast candidates. In contrast to the traditional lambic beer maturation phase, during the aging of sour-matured production-style beer, different biotypes of Saccharomyces cerevisiae dominated the cultivable in-house mycobiota, which were followed by Pichia membranifaciens, Brettanomyces bruxellensis, and Brettanomyces anomalus. In addition, three putative S. cerevisiae × Saccharomyces uvarum hybrids were identified. S. cerevisiae feral strains sporulated, produced viable monosporic progenies, and had the STA1 gene downstream as a full-length promoter. During hopped wort fermentation, four S. cerevisiae strains and the S. cerevisiae × S. uvarum hybrid WY213 exceeded non-Saccharomyces strains in fermentative rate and ethanol production except for P. membranifaciens WY122. This strain consumed maltose after a long lag phase, in contrast to the phenotypic profile described for the species. According to the STA1+ genotype, S. cerevisiae partially consumed dextrin. Among the volatile organic compounds (VOCs) produced by S. cerevisiae and the S. cerevisiae × S. uvarum hybrid, phenylethyl alcohol, which has a fruit-like aroma, was the most prevalent. In conclusion, the strains characterized here have relevant brewing properties and are exploitable as indigenous craft beer starters.

Sucrose Concentration and Fermentation Temperature Impact the Sensory Characteristics and Liking of Kombucha.

Kombucha is a fermented tea beverage consumed for its probiotics and functional properties. It has a unique sensory profile driven by the properties of tea polyphenols and fermentation products, including organic acids. Fermentation temperature and sucrose content affect the fermentation process and the production of organic acids; yet less is known about their impacts on the sensory profile and consumer acceptance. Thus, we aimed to examine the impact of sucrose concentration and fermentation temperature on sensory attributes and liking. For this study, kombucha tea was fermented at three different concentrations of sucrose and fermented at two temperatures for 11 days. Fermentation was monitored by pH, brix, and titratable acidity, and consumers (n = 111) evaluated the kombucha for sensory attributes and overall liking. The fermentation temperature resulted in significant differences in titratable acidity, with higher temperatures producing more organic acids, resulting in higher astringency, and suppressed sweetness. The lower fermentation was reported as significantly more liked, with no difference in liking between the 7.5% and 10% sucrose kombucha samples. Fermentation temperature had the greatest impact on the sensory profile rather than sucrose concentration, which had a greater effect on the fermentation rate and production organic acids.

Unveiling the power of adding sterols in wine: Optimizing alcoholic fermentation with strategic management

Excessive grape must clarification can result in sluggish alcoholic fermentation and sometimes alcoholic stuck fermentation, because of the lack of sterols for the yeasts growth. To avoid this risk, addition of sterols (ergosterol or phytosterols) can be performed, resulting in higher Saccharomyces cerevisiae viability and shorter fermentation duration. However, no dedicated study was implemented to evaluate the efficiency of different strategies of sterol management (considering sterol type, added concentration and timing of addition) during wine fermentation. So, first, to evaluate whether the response of wine yeast strains to sterol nutrition was similar according to the type and the concentration of the sterol present in the initial must, it was studied the response of a set of 10 S. cerevisiae strains in a synthetic grape must with low, medium and high concentrations of ergosterol or phytosterols. Then, the impact of the timing of sterol addition was evaluated on 2 S. cerevisiae strains with opposite behaviours. This work confirmed previous results concerning the role of ergosterol and phytosterols but also revealed new findings in this field. At first, it was confirmed that ergosterol played an important role in improving the maintenance of viable cells towards the end of fermentation, particularly in sterols-limited situations, while phytosterols demonstrated an ability to reduce acetate and glycerol production. But, in a second part, our study sheds new light on the beneficial impact of sterol addition on amino acid assimilation in yeast, leading to an increase in maximum fermentation rate, biomass production and percentage of viable cells. However, the main novelty of this research work concerns the timing of ergosterol addition. This addition at the start of fermentation in a phytosterols-free synthetic must enabled faster fermentations, as well as higher fermentative aroma synthesis, compared to addition during stationary phase Even if the impact of ergosterol additions were relatively similar for both strains tested, notable differences were found concerning amino acid assimilation and biomass production, suggesting differences in the regulation of nitrogen metabolism between both strains. These findings provide new insights into our understanding of sterol role in enological fermentation. It offers a basis for both the development of innovative strategies for sterol management and the selection of wine yeast strains under sterol starvation.

Single nucleotide polymorphisms associated with wine fermentation and adaptation to nitrogen limitation in wild and domesticated yeast strains

For more than 20 years, Saccharomyces cerevisiae has served as a model organism for genetic studies and molecular biology, as well as a platform for biotechnology (e.g., wine production). One of the important ecological niches of this yeast that has been extensively studied is wine fermentation, a complex microbiological process in which S. cerevisiae faces various stresses such as limited availability of nitrogen. Nitrogen deficiencies in grape juice impair fermentation rate and yeast biomass production, leading to sluggish or stuck fermentations, resulting in considerable economic losses for the wine industry. In the present work, we took advantage of the “1002 Yeast Genomes Project” population, the most complete catalogue of the genetic variation in the species and a powerful resource for genotype-phenotype correlations, to study the adaptation to nitrogen limitation in wild and domesticated yeast strains in the context of wine fermentation. We found that wild and domesticated yeast strains have different adaptations to nitrogen limitation, corroborating their different evolutionary trajectories. Using a combination of state-of-the-art bioinformatic (GWAS) and molecular biology (CRISPR-Cas9) methodologies, we validated that PNP1, RRT5 and PDR12 are implicated in wine fermentation, where RRT5 and PDR12 are also involved in yeast adaptation to nitrogen limitation. In addition, we validated SNPs in these genes leading to differences in fermentative capacities and adaptation to nitrogen limitation. Altogether, the mapped genetic variants have potential applications for the genetic improvement of industrial yeast strains.

Cell-specific rates of sulfate reduction and fermentation in the sub-seafloor biosphere.

Microorganisms in subsurface sediments live from recalcitrant organic matter deposited thousands or millions of years ago. Their catabolic activities are low, but the deep biosphere is of global importance due to its volume. The stability of deeply buried sediments provides a natural laboratory where prokaryotic communities that live in steady state with their environments can be studied over long time scales. We tested if a balance is established between the flow of energy, the microbial community size, and the basal power requirement needed to maintain cells in sediments buried meters below the sea floor. We measured rates of carbon oxidation by sulfate reduction and counted the microbial cells throughout ten carefully selected sediment cores with ages from years to millions of years. The rates of carbon oxidation were converted to power (J s-1 i.e., Watt) using the Gibbs free energy of the anaerobic oxidation of complex organic carbon. We separated energy dissipation by fermentation from sulfate reduction. Similarly, we separated the community into sulfate reducers and non-sulfate reducers based on the dsrB gene, so that sulfate reduction could be related to sulfate reducers. We found that the per-cell sulfate reduction rate was stable near 10-2 fmol C cell-1 day-1 right below the zone of bioturbation and did not decrease with increasing depth and sediment age. The corresponding power dissipation rate was 10-17 W sulfate-reducing cell-1. The cell-specific power dissipation of sulfate reducers in old sediments was similar to the slowest growing anaerobic cultures. The energy from mineralization of organic matter that was not dissipated by sulfate reduction was distributed evenly to all cells that did not possess the dsrB gene, i.e., cells operationally defined as fermenting. In contrast to sulfate reducers, the fermenting cells had decreasing catabolism as the sediment aged. A vast difference in power requirement between fermenters and sulfate reducers caused the microbial community in old sediments to consist of a minute fraction of sulfate reducers and a vast majority of fermenters.

The influence of yeast format and pitching rate on Scotch malt whisky fermentation kinetics and congeners

Yeast format and pitching rate are variables which can be easily manipulated in a distillery environment but are seldom altered. Fermentations using dried and liquid yeast were studied at laboratory scale and compared by application of a 4-parameter logistic model to measurements of the decline in apparent extract during fermentation. Congener analysis of new make distillate allowed comparison between compounds of interest produced during fermentation. The liquid yeast format demonstrated a significant reduction (p&lt;0.05) in lag time, which was 68% shorter than dried yeast. Despite this, longer overall fermentation times were observed due to a slower exponential phase as compared to the dried yeast format. Alteration of the yeast pitching rate using dried and liquid formats, demonstrated that high rates resulted in reduced lag times. The maximum fermentation rates (Vmax) were assessed from the fermentation models and no consistent trend could be identified. Dried yeast was observed to achieve its maximum fermentation rate when underpitched. Substantially higher Vmax ­values were obtained with overpitched liquid yeast fermentations, resulting in faster fermentations, compared to underpitched liquid yeast fermentations. The liquid yeast format created more esters compared to dried yeast. The concentration of ethyl esters generally trended downwards for fermentations pitched with less yeast which fully attenuated. By combining the results of these studies, distillers can make informed decisions to optimise spirit character, quality, and distillery production.

Effects of barley grain processing method (ground vs. steam flaked) and dietary protein content on growth performance, ruminal fermentation, and inflammatory indicators of Holstein dairy calves

We hypothesized that steam-flaking barley grain may improve ruminal fermentation rate and rumen development as well as reduce cecal fermentation rate through reducing starch escape to the lower parts of gastrointestinal trach (GIT) which can modulate inflammatory response of young calves. Therefore, the interaction effect of barley grain processing method (ground barley; GB vs. steam-flaked barley; SFB) and starter protein content (20% vs. 24%, DM basis) on growth performance, skeletal growth indices, ruminal fermentation, urinary purine derivatives and microbial protein synthesis, blood biochemical, and inflammatory indicators in Holstein dairy calves were evaluated. Fifty-two new-born Holstein female calves (3 day-old) were assigned to one of four treatments: 1) GB grain with 20% CP (GB-20CP); 2) GB grain with 24% CP (GB-24CP); 3) SFB grain with 20% CP (SFB-20CP); 4) SFB grain with 24% CP (SFB-24CP). Calves received 4 L/d whole milk from d 3–10, 7 L/d from d 11–45, 2 L/d from d 46–50 of the study followed by 1 L/d from d 51 and 52 of the study and had ad-libitum access to water and starters (d 1 to d 73). The greatest starter intake was observed in SFB-24CP diet during the pre-weaning period. Accordingly, calves fed this diet had higher weaning and final, body weight (BW), greater average daily gain (ADG) during the pre-weaning period and as well as higher weaning and final wither heights compared to other groups. Calves received starters contained SFB-24CP had higher ruminal concentration of short chain fatty acids (pre-weaning) and serum beta-hydroxybutyrate (BHB; pre-weaning; compared to other groups. The highest (428 pg/mL) and the lowest (359 pg/mL) concentrations of tumour necrosis factor-α (TNF-α) was observed in calves fed GB-20CP and SFB-24CP diets, respectively. Same trend was detected for serum amyloid A during pre-weaning period. Calves fed starters containing GB had looser feces, higher ruminal NH3- N concentration, and higher alanine aminotransferase (post-weaning) compared to those received SFB diets. Dairy calves fed 24CP had slight improvement in growth performance, particularly before weaning, compared to those fed 20CP. Based on the conditions of the present study, it can be concluded that feeding SFB grain may reduce starch flow to the lower sections of GIT and consequently reduce inflammatory responses of young claves compared to GB grain. Furthermore, concurrent feeding SFB and 24CP improved ruminal metabolism in calves which can be due to higher starch availability in the rumen. Further researches are needed to evaluate the effect of grains processing methods on ruminal and cecal microbial community.

Potential of indigenous legume fodder tree and shrubs to animal feed and mitigation of methane emission in the semi‐humid condition of southern Ethiopia

AbstractThe study was conducted to investigate the in vitro gas production characteristics and methane (CH4) emission potential of indigenous legume fodder trees and shrubs (ILFTS). The most predominant 11 ILFTS species were selected, and leaves and fruit/pod samples were collected, oven dried, and ground. The potential leaf biomass yield (PBY), dry matter (DM), ether extract, digestible crude protein, carbohydrate (CHO), acid detergent lignin, ash, total phenol, condensed tannin, gross energy, digestible energy, metabolizable energy (ME), gas production characteristics, CH4 emissions, organic matter digestibility (OMD), and short‐chain fatty acids (SCFA) were determined. ANOVA and independent t test were used to examine variation among species in plants nature and between fruits and pods within agroecosystems, respectively. Correlation analysis was used to determine relationships among parameters. The study indicated that only DM and CHO showed substantial variation in nutritional quality parameters among trees, shrubs, and fruit/pods in the lowlands. Fruits/pods and trees displayed significant differences in gas production characteristics in the lowlands, unlike shrubs, which had non‐substantial variations. Moreover, the PBY, CH4 emission, OMD, and ME of ILFTS revealed substantial variation (P &lt; .05) with species and among trees, shrubs, and fruits/pods in both agroecosystems. Besides, CH4 production showed a positive significant correlation with gas volume and (b) substantiating the effect of rate and degree of fiber fermentation on CH4 emission. It was discovered that there was a positive significant correlation between the 6 and 24 h incubation period, (c) which substantiated the need for optimal microbial density and substrate for high rate constant gas production of b (c). In conclusion, ILFTS produce considerable biomass rich in nutrients but vary in the degradability of CHO with plant nature, species, and forage origin. This elicits differences in gas production characteristics and CH4 emission with in vitro fermentation, resulting in differences in the corresponding OMD, ME, and SCFA values.

Plant cell wall composition modulates the gut microbiota and metabolites in in-vitro fermentation

This research investigated the effect of different types of plant cell wall fibres, including cereal (i.e., barley, sorghum, and rice), legume (i.e., pea, faba bean, and mung bean), and tuber (potato, sweet potato, and yam) cell wall fibres on in vitro faecal fermentation profiles and gut microbiota composition. The cell wall composition, specifically the content of lignin and pectin, was found to have a significant influence on the gut microbiota and fermentation outcomes. Compared with type I cell walls (legume and tuber) which have high pectin content, the type II cell walls (cereal) which are high in lignin but low in pectin had a lower fermentation rates and less short-chain fatty acid production. The redundancy analysis showed samples with similar fibre composition and fermentation profiles clustered together, and the principal coordinate analysis revealed separation among different types of cell walls and closer proximity among the same cell wall types. These findings emphasize the importance of cell wall composition in shaping the microbial community during fermentation and contribute to a better understanding of the relationship between plant cell walls and gut health. This research has practical implications for the development of functional foods and dietary interventions.

Long-term performance on volatile fatty acids production improved in a kitchen wastewater fermenter by co-fermentation of sludge and membrane separation

Kitchen wastewater can be transformed into a valuable resource through anaerobic fermentation. However, the efficiency of this process is hindered by various factors including salt inhibition and nutrient imbalance. In this study, we examined the effects of co-fermentation with sludge and membrane filtration on the anaerobic fermentation of kitchen wastewater. Our findings indicate that co-fermentation with sludge resulted in a 4-fold increase in fermentation rate and a 2-fold increase in short-chain fatty acids (SCFAs) production. This suggests that the addition of sludge helped to alleviate salt and acid inhibition through ammonia buffering and elemental balancing. The membrane filtration retained 60% of soluble carbohydrates and 15% of proteins in the reactor for further fermentation and recovered nearly 100% of NH4+ and SCFAs in the filtrate, which helped to alleviate acid and ammonia inhibition. The combined fermentation system significantly increased the richness and diversity of microorganisms, particularly caproiciproducens and Clostridium_sensu_stricto_12. The membrane flux remained stable and at a relatively high level, indicating that the combined process may be economically feasible. However, scaling up the co-anaerobic fermentation of kitchen wastewater and sludge in a membrane reactor is necessary for further economic evaluation in the future.