Yeast Sludge Research Articles

Aflatoxin B1-associated oxidative stress along with toxicopathological and immunological alterations is efficiently counteracted by dietary supplementation of distillery yeast sludge in broilers.

Aflatoxin B1 (AFB1) is among the most potent genotoxic and carcinogenic mycotoxins and is a major source of distress for the growing poultry sector. On the other hand, distillery yeast sludge or distillery sludge (DS) is a byproduct of molasses-based industries. It is often treated as a waste despite containing abundant nutrients particularly protein, basic amino acids, and vitamins along with other macro and micronutrients. This study was designed to investigate the oxidative stress and immunological alterations induced by AFB1 and their amelioration by dietary supplementation with DS. For this purpose, 360 newly hatched broiler chicks were randomly divided into twelve groups (30 birds each) and fed different combinations of AFB1 (100, 200, or 600µg/kg) and DS (5 or 10g/kg) for 42days. The parameters under consideration were body weight, feed conversion ratio (FCR), relative organ weights, histopathological examination of different visceral organs, total antioxidant capacity, antibody response to intravenous injection of sheep red blood cells, in situ lymphoproliferative response to phytohemagglutinin-P, and phagocytic potential through a carbon clearance assay system. The results of this study established that DS supplementation ameliorated AFB1-associated oxidative stress and ameliorated toxicopathological and immunological anomalies in groups given AFB1 at 100µg/kg and 200µg/kg; however, little to no relief was observed in birds fed AFB1 at 600µg/kg. The determination of the actual ratio of the AFB1 to the DS for substantiating the ameliorating effects requires further investigation.

Studying the Efficacy of Some Organic Compounds as a Source of Potassium Fertilization and their Effect on the Wheat-Peanut Crop System in Sandy Soil

To encourage sustainable agriculture and increase net revenue for the agricultural community, the use of expensive chemical fertilizers should be reduced and replaced with locally produced organic byproducts. For this reason, a field experiment was conducted on sand soil at Ismailia Agric. Res. Station in Ismailia Governorate, Egypt, to evaluate the impact of various organic K rates 0, 50%, 75%, and 100% from the recommended plant dose) and three different K organic sources i.e., seaweed (SWE), yeast sludge (YS), and filter mud cake (FMC), in two successive seasons of wheat (Triticum sativac. v. Giza 168) as a winter crop and peanut (Arachis hypogaeac. v. Giza 6) as a summer crop season; to study how responsive they are to different potassium rates and sources applied to crop productivity. After both crops were harvested, the chemical features of the soil were also assessed. The current findings state that the use of varied organic K rates and sources boosted the yield components of wheat and peanut crops, as well as the nutritional total content in straw, grains, or seed of both wheat and peanut, as compared to the control treatment. Furthermore, the application of all treatments improved pH, EC, OM, and cation exchangeable capacity (CEC); the availability of P, K, and soluble K followed a similar pattern after the wheat-peanut crop was harvested. Furthermore, the highest increases resulted from 75% of the recommended K dose, and the best organic sources of K were YS and SWE for wheat and peanut, respectively. In conclusion, the use of tested organic potassium sources is a good alternative to mineral potassium fertilizers, is economical, which is reflected in crop yield, and is environmentally friendly.

The effect of yeast autolysis on the composition of wine

The experiment aims to monitor the amino acid content, total polyphenolic components, and antioxidant activity values of wines that have matured on yeast and non-yeast sludge. The grape varieties used in the experiment, which lasted 300 days, were (Vitis vinifera L.) Chardonnay, Riesling rhinestone, and Veltliner green. During this time, both the measured parameters and the characteristics of the wine gradually changed. The total amount of amino acids in the wines aged on yeast sludge was more than 200% greater than that found in wines aged without yeast sludge. A 30% decrease in the total polyphenolic component content was noted for wines produced with yeast lees. The antioxidant activity levels correlated with the total polyphenol content, with the levels in wines made with yeast lees on average 13% lower. The experiment showed that wines produced by these different methods have different mutagenic characteristics. Sensory analysis of the wines demonstrated that wines matured on yeast sludge have better organoleptic properties. These wines were sturdier, fuller, and more harmonious than wines aged without a yeast sludge.

Biological recovery of phosphorus (BioP-Rec) from wastewater streams using brewer's yeast on pilot-scale.

Most recent advances for phosphorus (P) recovery using brewery yeast on laboratory scale were used to scale up to a pilot-scale process (BioP-Rec module) and applied in a full-scale wastewater treatment plant (WWTP). A P balance was established for WWTP Markranstädt according to two thresholds: (1) the economic feasibility threshold for P recovery of 0.05kg/m3 of free P, and (2) the German Sewage Sludge Ordinance (GSSO) threshold, which demands that all WWTPs with a P content in dry matter (DM) of biosolids of 20 gP/kgDM or higher in the coming years must perform mandatory P recovery. In terms of defined thresholds, return and excess sludges were identified as the most feasible WWTP process streams for P recovery. In a 1 m3 BioP-Rec module a 3 stage process was established. From the P-rich water-phase of the return sludge produced in stage 1, which contained 0.051kg/m3 of free P, 77.56% was taken up by P-depleted brewer's yeast Saccharomyces pastorianus in 3h in stage 2. In stage 3, the yeast was concentrated in 1h to produce yeast sludge as a fertilizer product. We demonstrated a novel pilot-scale process for the production of bio-based P-rich fertilizer.

Biofouling of hollow fiber ultrafiltration membranes: A novel multiphase CFD – Porous - CES model and experimental study

The present study focuses on developing a multiphase CFD – porous- CES model to investigate the effect of biofouling in a membrane reactor. An experimental setup with an ultrafiltration (UF) hollow fiber (HF) membrane was constructed to understand the deposition and development of the cake layer due to biofouling. The CFD – porous sub-models were used to study the effect of hydrodynamics on fouling. While the CES (combined extracellular polymeric substances (EPS) and soluble microbial product (SMP)) sub-model incorporated the effect of EPS and SMP on the cake layer formation. The EPS and SMP fractions constitute a significant portion of the microbial mass and are critical in analyzing the biofouling in UF and microfiltration (MF) membranes. The developed membrane fouling model was validated with both literature experimental results and experimental observations from the laboratory-scale UF-HF membrane setup. It was observed that the effect of cake deposition on transmembrane pressure (TMP) and permeate flux was 1.5% higher for experimental set 2 (synthetic wastewater with sludge seeding) as compared to experimental set 1 (synthetic wastewater with yeast sludge). Also, the maximum percentage error between the experimental and simulation values was ±6.2%, thus validating the model. The validated model was then used to investigate the sensitivity of the CES sub-model by comparing it with the sectional resistance model (a commonly used model in literature for predicting membrane fouling). It was observed that the sectional resistance model underpredicted the mass of cake deposited by 13% and overpredicted the limiting flux by 4%. The limiting flux has a significant effect while designing a membrane system, and its accurate prediction helps prevent premature fouling in UF membranes. Hence, the preceding results suggest the importance of accounting for the influence of EPS and SMP on the cake layer formation and biofouling and the relevance of the current study.

Assessment of Aflatoxins production and its various Control strategies: A Review

Mycotoxins specifically the aflatoxins contaminate about 25% of the agricultural products in the world. They effect greatly the growth rate, feed intake, and feed conversion ratio. There is a great economical loss to farmers due to loss of food values and effecting human as well as animal health. The different preventive measures are in use to control fungal contamination such as chemicals (acids, bases, and salts), HSCAS ,zeolite polymers, activated charcoal and yeast with variable findings. Fraction of yeast sludge has proved to minimize the adverse effects of aflatoxicosis due to the presence of manno-oligosaccharides in its cell wall. The present review highlights the remedial measures particularly yeast sludge to control aflatoxicosis.

Kinetics of MSW Biodegradation with Different Inocula In Laboratory In-Vessel Reactor

The in-vessel composting is considered as an environmentally sound method for the treatment and disposal of Municipal Solid Waste (MSW) as it produces good quality compost with lesser environmental impacts. In this study, the process was accelerated and the composting time was reduced using various industrial organic wastes as inoculums in a vertical in-vessel reactor with stirrer arrangement. This study examined the process kinetics which aims to show the interdependency between biological, chemical & physical factors. It is also the extension of the previous work which dealt with composting of the organic fraction of municipal solid waste. The rate of degradation of volatile solids, TOC and C/N ratio are presented in First-order kinetic model and reaction rate constants are determined. The different inoculums used are yeast sludge, spent wash, distillery effluent and sugar sludge. Yeast sludge has the highest R2 values such as 0.979, 0.978 and 0.986 for VS, TOC and C/N ratio respectively. The R2 value of C/N ratio for the sugar sludge is 0.983. From the kinetic study, it can be concluded that the yeast sludge can be a better option when compared with other sludge to accelerate the process of composting.

Control of Aflatoxins in Poultry Feed by Using Yeast

The present study aimed to determine the detoxification potential of the food industry by-products such as yeast sludge against the harmful effects of aflatoxins on broilers. The objective of this study was to compare the binding capacity of yeast sludge fractions i.e. yeast sludge cell wall (YSCW) and yeast sludge cell solubles (YSCS) against different levels of AFB1 and AFG1. Yeast sludge was sonicated into yeast sludge cell walls and yeast sludge cell soluble. A total of 300 one-day-old chicks were randomly divided into 10 treatments with three replicates per treatment and ten chicks per replicate. The 10 treatments included negative control, three positive control with different levels of AFB1 and AFG1, and three different adsorbents with different levels of combinations of AFB1 and AFG1. AFB1 and AFG1 treatments were offered with different levels of AFs (50, 100, and 150 µg/kg) without toxin binder in the feed while the remaining treatments included 0.5% YSCW and 0.5% YSCS as toxin binders at different levels of AFB1 and AFG1 in a factorial arrangement. Feed and water were provided timely with great accuracy. The Aflatoxins showed a significant effect on production, slaughtering, and serum chemistry parameters. The yeast sludge cell wall exhibited significant effects on the production and slaughtering parameters of chicks. Yeast sludge cell wall also showed a significant effect on the biochemical and mineral profile of chicks. The results confirmed that natural binders are economically effective in commercial poultry production.

Yeast sludge and its components ameliorate ochratoxin Ainduced toxicity in broiler chicks

Purpose: To investigate the protective effect of yeast sludge (YS) and its components against ochratoxin A (OTA) in broiler chicks.
 Methods: Ochratoxin A (OTA) was produced through solid state fermentation, and quantified using high performance liquid chromatography (HPLC). A total of 1250 one-day old broiler chicks of Arbreaker breed were randomly assigned to five diet groups (A - E) replicated five times in such a way that each replicate had 50 chicks. The five diet groups were: A (normal poultry feed), B (200 µg/kg OTA), C (200 µg/kg OTA plus 2 g/kg YS), D (200 µg/kg OTA plus 2 g/kg yeast sludge cell mass, YSCM), and E (200 µg/kg OTA plus 2 g/kg yeast sludge cell wall (YSCW). The study lasted 35 days. Indices of liver and kidney functions were determined, as well as histopathological examination of samples of kidney, liver and bursa of Fabricius.
 Results: Supplementation of chicks diet with OTA at a dose of 200 ppb significantly reduced serum levels of total protein (TP), albumin, and creatinine, but significantly raised the activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (p < 0.05). However, inclusion of YS, YSCM, and YSCW in OTA-contaminated diet significantly reversed the effect of OTA on the indices of liver and kidney functions (p < 0.05). Yeast sludge and its components also significantly ameliorated OTA-induced histological changes in the liver, kidney and bursa of Fabricius.
 Conclusion: These results indicate that YS and it components improve hepatorenal function and histological changes induced by OTA.

Promotion of Osteoblast Proliferation Activated by Betaglucan (BG) Derived from Yeast Sludge

In tissue engineering, biomaterials used for bone tissue substitutes attract increasing interests, especially for finding biologically active compounds that can activate proliferation of osteoblastic MG63 cells. The evaluation of the impact of a soluble yeast-derived β-(1-3), (1-6)-D-glucan (BG) extracted from distillery waste yeast sludge on viability and proliferation of MG63 cells was studied. Spray dried BG prepared from alkaline extraction was used as supplementary activator in osteoblastic cell culture system. The composition of BG was characterized using FTIR spectral analysis and BG analysis assay kit. MG63 human osteoblast cell-line was cultured on Dulbecco’s modified’s medium supplemented with various concentrations of BG ranging from 0.1 to 1.0 mg/mL. The cells were cultured up to 7 days under a humidified 5% CO2 atmosphere at 37°C and monitored the level of proliferation at pre-determined intervals. Results showed that increase in BG concentration substantially promoted MG63 cell proliferation. Optimal concentration was identified and found at 0.3 - 0.7 mg/mL. Results revealed that BG could be further utilized for the upregulation of osteoblastic proliferation positively related to the acceleration of bone regeneration.

Isolation and screening of aflatoxin-detoxifying yeast and bacteria from ruminal fluids to reduce aflatoxin B1 contamination in dairy cattle feed.

To obtain yeast and bacteria from ruminal fluids that possess aflatoxin B1 (AFB1 ) detoxifying ability for use in animal feed. Sources of isolation were ruminal fluids of three nonfistulated dairy cows, fed diets containing cassava pulp, rice straw or distillery yeast sludge. The isolation was carried out to screen for the isolates that were active in both anaerobic and aerobic conditions. Three yeast and three bacteria isolates were selected. Up to 85% of AFB1 was detoxified by yeast isolates and up to 60% AFB1 reduction was evident by bacteria isolates. Two yeast isolates were identified as Kluyveromyces marxianus and one isolate as Pichia kudriavzevii. The three bacteria isolates were identified as Enterococcus faecium, Corynebacterium phoceense and C. vitaeruminis. All strains showed high biomass production when cultivated in medium with 80gl-1 glucose. The isolated yeast and bacteria with AFB1 detoxifying ability showed a good potential to be applied as an aflatoxin-detoxifying agent to ingredients used to feed dairy cattle. The abilities of isolates to survive and be active in anaerobic and aerobic conditions rendered them to be active in cattle's rumen. Their biomass could be produced in bulk and used as feed supplement for aflatoxin detoxification in dairy cattle.

Effect of distillery yeast sludge on growth performance, nutrient digestibility and slaughter parameters in Japanese quails

This study was planned to evaluate the effect of distillery yeast sludge (DYS) as a protein source on growth performance, nutrient digestibility and slaughtering parameters in Japanese quail birds. For this purpose, six hundred day-old quails were randomly distributed into six dietary treatments. These dietary treatments were; G1 (Control Group) fed a basal diet (CP 24%, ME 2900 kcal/kg) without DYS, while other dietary treatments were G2, G3, G4, G5 and G6 fed basal diet containing DYS @ 1.5, 3.0, 4.5, 6.0 and 7.5%, respectively. It was observed that feed intake and weight gain tended to increase (P < 0.05) up to 3% DYS. Better (P < 0.05) feed conversion ratio (FCR) was observed in birds fed diet containing DYS at the level of 1.5 and 3%. Dry matter and crude protein digestibility decreased with increasing levels of DYS (P < 0.05). Cost of production per 100 g of weight gain was also less in birds fed diet containing 3% DYS. Study revealed that inclusion of distillery yeast sludge in the diet of Japanese quails up to 3% improves the growth performance and economics efficacy.

Effect of Chinese rice wine sludge on the production of Chinese steamed buns

Chinese rice wine sludge (CRWS), analogous to beer yeast sludge, is the filter cake remaining after squeezing the fermentation mash of Chinese rice wine. CRWS contains high levels of protein (44.74%), nonstructural carbohydrates (37.33%), crude fiber (13.5%), and essential amino acids, which could enhance the trophic value of Chinese steamed buns. In our research, the microbiota of CRWS (mainly Saccharomyces cerevisiae and Lactobacillus sp.) was analyzed at the species level by single-molecule real-time DNA sequencing technology. Interestingly, the microbiota of CRWS was similar to that of the starter dough typically used to prepare Chinese steamed buns. Incorporation of CRWS significantly influenced the pasting properties and farinograph characteristics of the dough, which control the texture of the Chinese steamed buns, and supplementation with 5∼30% CRWS caused the properties of the resulting buns to be more similar to those of northern-style steamed buns. CRWS addition also significantly enhanced the content of aroma compounds in the Chinese steamed buns. Practical applications In China, approximately three million tons of CRWS is produced per year, and the reutilization of CRWS is a challenge faced by the Chinese rice wine industry. Meanwhile, Chinese steamed buns prepared with CRWS are becoming increasingly popular, and CRWS has been used in the preparation of homemade Chinese steamed buns. However, the use of CRWS in the industrial production of Chinese steamed buns has not yet been developed. The productive use of CRWS could have substantial economic benefits. In this study, the effect of CRWS incorporation on Chinese steamed buns is reported for the first time. The results showed that CRWS improved the quality of Chinese steamed buns. The results of this study suggest a simple and convenient method for incorporating CRWS into the industrial production of northern-style Chinese steamed buns.

Design, development and performance evaluation of distillery yeast sludge dryer

Abstract The poultry industry is rapidly growing in Pakistan and feed for broilers are going to be a big issue. A huge quantity of distillery yeast sludge (16,000 t/year), having high moisture content (85%) produced by different industries, is one of solutions regarding feeding issues in the broiler industry. To reduce moisture content, a dryer has been developed, and the comparative performance of distillery yeast sludge dryer with respect to a conventional dryer was evaluated. It was found that a distillery yeast sludge dryer gives the best nutritional characteristics, namely, moisture contents of 27.42%, protein contents of 22.42%, nitrogen contents of 3.02%, phosphorous contents of 3.6%, fat contents of 2.14%, potassium contents of 5.0%, ash contents of 39.93%, and fiber contents of 0.0031% of dried sludge for sample weight of 600 kg and drying for a period of 6 h, resulting in the best quality of sludge to use as poultry feed and organic manure.

Amelioration of immunosuppressive effects of aflatoxin and ochratoxin A in White Leghorn layers with distillery yeast sludge

The present study was carried out with the objectives to thrash immunotoxic effects of moldy feed in commercial White Leghorn layers and to know either addition of distillery yeast sludge (DYS) in moldy feed ameliorates the immunotoxic effects or not. For this purpose, moldy feed was prepared containing OTA and AFB1 56 and 136 μg/kg, respectively. For this purpose, 100, 40-week-old White Leghorn hens were procured and kept under standard management conditions. Birds were divided into five equal groups. Birds were kept on moldy feed (ochratoxin A: 56 μg/kg and aflatoxin B1: 136 μg/kg) mixed with 0%, 0.5%, 1% and 2% DYS/kg moldy feed. Group A served as control. Blood was collected without anticoagulant to separate serum. Serum ALT, creatinine and blood urea levels significantly increased in moldy-fed group as compared to control group, while nonsignificantly different readings of serum ALT, creatinine and blood urea were recorded in moldy feed + 2% DYS and control group. Immune parameters, that is, lymphoproliferative response to PHA-P, phagocytic potential and total protein and IgG titers against sheep RBCs were significantly decreased in birds receiving moldy feed as compared to control group. Almost all parameters studied were normal compared to control group with the addition of 2% DYS in moldy feed, while 1% DYS partially ameliorated the immunotoxic effects of mycotoxins.

Mycota of distillery yeast sludge as source of single cell protein

This study focused on the isolation, identification, and utilization of the mycota present in distillery yeast sludge as source of single cell protein. Seven fungal isolates were described and identified. These include three species of yeasts (Saccharomyces cerevisiae Meyen ex E.C. Hansen, Candida parapsilosis (Ashford) Langeron and Talice, and Candida guilliermondii (Castellani) Langeron et Guerra) and four species of molds (Aspergillus flavus Link, Aspergillus niger van Teigh, Aspergillus japonicus Saito var japonicus, and Rhizopus sp.). The ability of the fungal isolates to produce single cell protein was evaluated by determining the crude protein content (CPC) of the distillery yeast sludge after 14 days of solid state fermentation. Results revealed that inoculation of the seven taxa produced significantly higher percentage CPC of the distillery yeast sludge. Apparently, S. cerevisiae-treated distillery yeast sludge had the highest percentage CPC of 33.7% and the highest percentage increase in CPC of 34.3%, while Rhizopus sp.-treated distillery yeast sludge had the lowest of 21.8%. Thus, the present study indicates the great potential of the seven taxa as source of single cell protein using the distillery sludge as substrate.

Treatment of, and Candida utilis biomass production from shochu wastewater; the effects of maintaining a low pH on DOC removal and feeding cultivation on biomass production

Shochu wastewater (SW; alcoholic distillery wastewater) contains large amounts of organic compounds (25,000 – 60,000 COD mg/L), nitrogen (1,000 – 6,000 T-N mg/L), and phosphorus (500 – 1,000 T-P mg/L). Despite its high nutrient content, SW is highly perishable, which limits its utilization for animal feed and fertilizer. Therefore, SW is mainly treated by methane fermentation. On the other hand, a feed yeast, Candida utilis, can utilize various organic compounds and be utilized as a yeast extract source and animal feed. We previously bred a mutant, C. utilis UNA1, that accumulates a large amount of nitrogen. Here, we investigated the use of C. utilis UNA1 to treat highly concentrated SW. With fed-batch cultivation using a 5-L jar fermenter, controlling pH at 5.0 with H2SO4, 62.9% of DOC, 38.4% of DTN, and 44.5% of DTP were stably removed from non-diluted barley shochu wastewater (BSW), and about 16.7 kg of freeze-dried yeast biomass was obtained. The yeast sludge biomass generated from BSW contains about 60% crude protein. Furthermore, using H2SO4 to control pH increased the sulfur content of wastewater, which increased the methionine composition of yeast sludge biomass.

Spent brewery yeast sludge as a single nitrogen source for fibrinolytic enzyme production of Virgibacillus sp. SK37

The objectives of this study were to investigate the suitable food industrial byproducts and conditions affecting proteinase production of Virgibacillus sp. SK37 as well as to evaluate fibrinolytic activity of secreted proteinases. Among 5 food industrial wastes including soybean pomace, rice bran, mungbean protein, spent brewery yeast sludge (Ys), and fish sauce sludge, Ys was the best nitrogen source for proteinase production from Virgibacillus sp. SK37. The highest level of proteinase production was obtained in the medium containing 1% Ys, 2.5% NaCl, pH 7.5 at 40°C, which was about 1.7 times higher than the commercial yeast extract medium. Virgibacillus sp. SK37 proteinases completely hydrolyzed fibrinogen within 50 min with Aα-chain being the first target and followed by Bβ- and Γ-chains. Virgibacillus sp. SK37 could be a potential source of fibrinolytic enzyme that can be developed as a functional food ingredient.

Nutritional evaluation of distillery sludge and its effect as a substitute of canola meal on performance of broiler chickens.

The study was conducted to investigate the chemical composition of distillery yeast sludge and its inclusion in broiler diets to replace canola meal. Raw distillery yeast sludge was washed with water using water and sludge in the ratio 6:1, respectively. Proximate analysis of raw distillery yeast sludge and washed distillery sludge was carried out for crude protein (CP), true protein (TP), ether extract (EE), ash, acid insoluble ash and nitrogen free extract (NFE) determination. Mineral contents and amino acid profile of raw distillery yeast sludge and washed distillery sludge were also determined. After chemical evaluation, four iso-caloric and iso-nitrogenous broiler starter and finisher diets were prepared in mash form using 0 (control), 4, 8 and 12% levels of washed distillery sludge replacing canola meal. One hundred and twenty day-old broiler chicks were randomly distributed into 12 experimental units in such a way that each diet was offered to three experimental units, each comprising of 10 chicks. It was observed that washing affected the nutrients either by decreasing or increasing their concentration. It decreased the total mineral contents whereas CP, TP, EE and NFE contents increased. Washing also increased amino acid profile. Average feed intake and weight gain were higher in birds fed diet containing 8% washed distillery sludge and lower in birds fed diet containing 0% washed distillery sludge. Feed cost per kg live weight gain decreased significantly as the level of washed distillery sludge was increased in the diet. Average heart, liver and pancreas weights decreased with increased level of washed distillery sludge in the diet. The study revealed that after washing, distillery yeast sludge can be used successfully in broiler diets up to the level of 8% without any adverse effect on broiler’s performance.

Corn stover-enhanced cellulase production by Aspergillus niger NRRL 567

The production of extracellular cellulases by Aspergilus niger NRRL 567 on corn stover was studied in liquid state fermentation. In this study, three cellulases, exoglucanase (EXG), endoglucanase (EG) and β-glucosidase (BGL) were produced by A. niger NRRL 567. The optimal pH, temperature and incubation time for cellulases production was found to be 3.5, 30°C and 96 h, respectively. Maximal cellulases activities were achieved with 4% corn stover, 0.1% molasses and 1% yeast sludge. To our knowledge, this is the first report on production of cellulases by using corn stover as a substrate from A. niger NRRL 567.