Wheat bran biodegradation by edible Pleurotus fungi – A sustainable perspective for food and feed

Supplementation with Aspergillus fungi strain cultures on wheat bran on low-protein diets on performance, egg quality and blood characteristics of laying hens

1. In the contemporary economic-industrial world, ensuring the quality of poultry products through the use of healthy birds and providing nutritious diets has gained particular importance. The objective of this experiment was to evaluate the optimisation of laying hens' diets by reducing dietary protein by 4.61% and replacing it with 1.5 g/kg fermented wheat bran using two strains of Aspergillus niger and two strains of Aspergillus oryzae.2. This study was conducted on 240 laying hens at 41 weeks of age over 16 weeks, organised into four treatments and two control groups. One of the control groups included a diet with normal protein (CH) and another group with 4.61% less protein (CL). Both control groups received 1.5 g/kg raw wheat bran with their diet. In contrast, the four experimental treatments (N0, N4, O3, O4) received a diet with 4.61% less protein and 1.5 g/kg fermented wheat bran by their respective fungal strains, including two strains of A. niger-50101 (N0) and 92 844 (N4) and two strains of A. oryzae-5163 (O3) and 5164 (O4).3. The highest free radical scavenging activity, iron ion regenerative power and anticoagulant activity were observed in the control group containing uncultivated bran (p<0.05). A significant reduction in phytate content and an increase in total phenolic compounds in the fermented bran extract N4 fungi were observed (p<0.05). Additionally, this group showed the lowest level of egg yolk oxidation, as indicated by the induced malondialdehyde reaction.4. The N0 treatment had the highest feed intake and antioxidant activity in blood serum compared to the other groups (p < 0.05). The O4 group had the highest egg mass and egg weight, as well as the lowest levels of triglycerides and oxidation in the egg yolk compared to the other groups (p < 0.05).5. This study showed that fermenting wheat bran with Aspergillus spp. could enhance its antioxidant properties, which in turn improves egg quality.

Beeswax waste improves the mycelial growth, fruiting body yield, and quality of oyster mushrooms (Pleurotus ostreatus)

Heilongjiang Province has the third largest bee population in China, producing over 2,000 tons of beeswax waste (BW) each year. Most of this BW is discarded or burned. Therefore, we urgently need to find sustainable applications of BW. Pleurotus ostreatus mushrooms, commonly referred to as oyster mushrooms, are cultivated for both food and medicine. The substrate used to grow P. ostreatus mushrooms often contains wheat bran as a nitrogen source. The goal of this study was to explore the feasibility of substituting this wheat bran with BW to cultivate P. ostreatus mushrooms. Five treatments were established, with BW making up 0%, 3%, 5%, 7%, and 9% of the total substrate, and the effects on the mycelial growth and development, biological efficiency (BE), and yield were evaluated along with changes in the chemical biomass composition of the fruiting bodies. Adding BW increased the number of days needed for primordia initiation and the number of days between flushes of P. ostreatus mushrooms. With increasing BW, the total fresh weight of P. ostreatus mushrooms first increased and then decreased. The 5% BW treatment resulted in the highest yield and biological efficiency (BE) of 1,478.96 ± 9.61 g bag-1 and 92.43 ± 0.60%, respectively, which exceeded the values of the control by 4.14% (control: 1,420.15 ± 9.53 g bag-1 and 88.76 ± 0.60%, respectively). The 5% BW treatment also resulted in the highest mushroom crude protein content (23.47 ± 0.18 g 100 g-1), which was 28.18% higher compared with the control (18.31 ± 0.05 g 100 g-1). The 9% BW treatment resulted in the highest crude polysaccharide content (10.33 ± 0.76 g 100 g-1), which was 2.42-fold that of the control (4.26 ± 0.30 g 100 g-1). This study suggests that BW could serve as an effective source of nitrogen to cultivate P. ostreatus. BW is a promising, cost-effective, and efficient additive to mushroom substrate, improving the yield and quality of P. ostreatus mushrooms while providing a sustainable use for an otherwise difficult to dispose of waste product.

Fungi as biotechnological allies: Exploring contributions of edible and medicinal mushrooms

Edible and medicinal mushrooms possess excellent nutritional properties due to their incredible versatility in growing on different substrates and producing extracellular enzymes with a wide range of specificity. These features make them excellent candidates for various biotechnological applications. In this context, biotechnological applications using edible and medicinal mushrooms can focus on the bioprocessing of agro-industrial wastes, an economical and environmentally friendly strategy. This review, based on recent original research and scientific reviews, highlights the versatility and potential of mushrooms in terms of sustainability and efficiency. We emphasized the biotechnological applications of edible and medicinal mushrooms and their enzymes including food production with high nutraceutical value by enhancing the quality and flavor of food industry products. Other biotechnological applications addressed in this review were cosmeceutical and biomedical development using mushroom extracts with bioactive compounds; wood pulp pretreatment processes in the pulp and paper industry; bioethanol production; and bioremediation for decontaminating soils and polluted effluents. These applications explain how edible and medicinal mushrooms have gained significance in biotechnology over the years, opening new avenues for innovation. The current tendency to study edible and medicinal mushrooms has gained the attention of researchers because these are still less known organisms becoming an attractive and natural source of novel bioactive compounds that could be integrated into a circular model production.

Effect of Pleurotus eryngii mycelial fermentation on the composition and antioxidant properties of tartary buckwheat

In this study, we investigated the effect of solid-state fermentation of Pleurotus eryngii on the composition and antioxidant activity of Tartary buckwheat (TB). Firstly, the solid-state fermentation of P. eryngii mycelium with buckwheat was carried out, and the fermentation process was explored. The results of the extraction process and method selection experiments showed that the percolation extraction method was superior to the other two methods. The results of extraction rate, active components and antioxidant activity measurements before and after fermentation of TB extract showed that the extraction rate increased about 1.7 times after fermentation. Total flavonoids, rutin and triterpene contents were increased after fermentation compared to control. Meanwhile, LC-MS results showed an increase in the content of the most important substances in the fermented TB extract and the incorporation of new components, such as oleanolic acid, ursolic acid, amino acids, and D-chiral inositol. The fermented TB extract showed stronger antioxidant activity, while the protein and amino acid contents increased by 1.93-fold and 1.94-fold, respectively. This research was the first to use P. eryngii to ferment TB and prepared a lyophilized powder that could be used directly using vacuum freeze-drying technology. Not only the use of solid-state fermentation technology advantages of edible fungi to achieve value-added buckwheat, but also to broaden the scope of TB applications. This study will provide ideas and directions for the development and application of edible mushroom fermentation technology and TB.

Enzymatic degradation of cellulose in soil: A review

Cellulose degradation is a critical process in soil ecosystems, playing a vital role in nutrient cycling and organic matter decomposition. Enzymatic degradation of cellulosic biomass is the most sustainable and green method of producing liquid biofuel. It has gained intensive research interest with future perspective as the majority of terrestrial lignocellulose biomass has a great potential to be used as a source of bioenergy. However, the recalcitrant nature of lignocellulose limits its use as a source of energy. Noteworthy enough, enzymatic conversion of cellulose biomass could be a leading future technology. Fungal enzymes play a central role in cellulose degradation. Our understanding of fungal cellulases has substantially redirected in the past few years with the discovery of a new class of enzymes and Cellulosome. Efforts have been made from time to time to develop an economically viable method of cellulose degradation. This review provides insights into the current state of knowledge regarding cellulose degradation in soil and identifies areas where further research is needed.

Use of oyster mushrooms (Pleurotus ostreatus) for increased circularity and valorization of rapeseed residues

In Europe, rapeseed is a common oilseed crop, resulting in the production of 20 million tons of rapeseed press cake yearly. This press cake can be further upcycled and a protein fraction can be extracted for food purposes, leaving de-proteinized fiber-rich residues. This study examined the use of these residues in the production of oyster mushrooms (Pleurotus ostreatus) and of the spent substrate as feed, since mushroom cultivation may improve the feed properties of substrate. In terms of mushroom production, the addition of rapeseed press residues was beneficial, giving significantly higher biological efficiency (BE = 93.1 ± 11.0%) compared with the control, sugar beet pulp substrate (70.0 ± 6.6%). This increase in productivity can most likely be explained by higher energy content in the substrate supplemented with lipid-rich rapeseed residues. Despite differences in BE between the substrates, high similarity was observed in lipid composition of the fruiting bodies (lipid profile dominated by linoleic acid (18:2), palmitic acid (16:0), and oleic acid (18:1)), and in protein and moisture content. After mushroom harvest, approximately 70% of the initial dry weight of both substrates remained as a possible feed source. Both substrates had significantly lower levels of carbohydrates and unchanged neutral detergent fiber content after mushroom harvest, and both gave lower in vitro digestibility, total gas production, and methane production. However, protein concentration differed between the substrates, with the highest concentration (15.8% of dry weight) found in spent substrate containing rapeseed press residues. The result of the present study suggests that the de-proteinized rapeseed press residue is a resource well-suited for use in the production of mushrooms and feed.

Soybean oil addition to wheat bran-based diet improves laying hens' performance

Background and Aim

Wheat bran (WB) is used extensively in animal feed. Despite its nutritional value, its use is limited because of its high-fiber content. We evaluated the effect of soybean oil on laying hen performance with maize meal partly replaced by WB.

Materials and Methods

Thirty-six ISA Brown laying hens, 40 weeks old, were used in a completely randomized design in which laying hens were distributed in individual cages, with three replications of four birds and assigned to three treatments: T1 (basal diet), T2 (60% basal diet + 20% maize meal + 20% WB), and T3 (60% basal diet + 20% maize meal + 17.5% WB + 2.5% soybean oil).

Results

Compared with the control group (T1), replacing 20% of yellow maize with WB (T2) did not affect average live weight, egg laying rate, soft-shelled egg production, egg mass, feed conversion per dozen eggs, or laying hen viability (p > 0.05). When 20% of the maize meal was replaced with WB, feed intake and feed conversion per egg mass increased (p < 0.05). Furthermore, adding 2.5% soybean oil to feed containing WB improved laying hen performance by significantly reducing feed conversion per egg mass (p < 0.05).

Conclusion

Adding 2.5% soybean oil to diets containing WB instead of 17.5% yellow maize improved the feed conversion per egg mass performance of laying hens.

Edible fungi efficiently degrade aflatoxin B1 in cereals and improve their nutritional composition by solid-state fermentation

Aflatoxin B₁ (AFB₁) is extremely harmful to human and livestock. Laccase, a green catalyst, has been shown to effectively degrade AFB₁ and can be obtained from edible fungi. The objective of this study was to screen edible fungi with high laccase activity and determine their effects on the degradation of AFB₁ in cereals and the nutritional composition of the cereals through solid-state fermentation. Results from plate assays confirmed that 51 of the 55 tested edible fungi could secrete laccase. Submerged fermentation results showed that 17 of the 51 edible fungi had maximum laccase activity exceeding 100 U/L. The growth of different edible fungi varied significantly in corn, rice and wheat. More importantly, 6 edible fungi with high laccase activity and good growth could efficiently degrade AFB₁ in cereals. We found for the first time that Ganoderma sinense could not only secrete highly active laccase and efficiently degrade AFB₁ in corn by 92.91%, but also improve the nutritional quality of corn. These findings reveal that solid-state fermentation of cereals with edible fungi is an environmentally friendly and efficient approach for degrading AFB₁ in cereals and improving the nutritional composition of cereals.

Novel processing strategies to enhance the bioaccessibility and bioavailability of functional components in wheat bran

Dietary fiber, polysaccharides and phenols are the representative functional components in wheat bran, which have important nutritional properties and pharmacological effects. However, the most functional components in wheat bran exist in bound form with low bioaccessibility. This paper reviews these functional components, analyzes modification methods, and focuses on novel solid-state fermentation (SSF) strategies in the release of functional components. Mining efficient microbial resources from traditional fermented foods, exploring the law of material exchange between cell populations, and building a stable self-regulation co-culture system are expected to strengthen the SSF process. In addition, emerging biotechnology such as synthetic biology and genome editing are used to transform the mixed fermentation system. Furthermore, combined with the emerging physical-field pretreatment coupled with SSF strategies applied to the modification of wheat bran, which provides a theoretical basis for the high-value utilization of wheat bran and the development of related functional foods and drugs.

Impact of Fermented Wheat Bran Dietary Fiber Addition on Dough Rheological Properties and Noodle Quality

This study aimed to evaluate the effect of fermented wheat bran dietary fiber (FWBDF) on the rheological properties of the dough and the quality of noodles and to compare it with the effect of the unfermented WBDF (UWBDF). WBDF was fermented with Auricularia polytricha. The results showed that adding UWBDF/FWBDF increased the storage modulus G' and loss modulus G” of the dough, converted α-helices and β-turns into β-sheets and random coils, respectively, inhibited water flow, increased cooking loss, and decreased the maximum resistance in the noodles. The formed gluten network had a more random and rigid structure, resulting in the deterioration of the quality of noodles. Furthermore, the number of α-helices and the peak proportions of weakly bound water A₂₂ increased but the number of β-sheets and cooking loss decreased in the FWBDF group compared with the UWBDF group. FWBDF (≤4%) improved the hardness of noodles, while UWBDF decreased it. These changes indicated that fermentation could reduce the destructive effects of WBDF on the quality of noodles, providing a new perspective on balancing dietary fiber-rich and high-quality foods.

Fungal lignocellulolytic enzymes and lignocellulose: A critical review on their contribution to multiproduct biorefinery and global biofuel research

The continuous increase in the global energy demand has diminished fossil fuel reserves and elevated the risk of environmental deterioration and human health. Biorefinery processes involved in producing bio-based energy-enriched chemicals have paved way to meet the energy demands. Compared to the thermochemical processes, fungal system biorefinery processes seems to be a promising approach for lignocellulose conversion. It also offers an eco-friendly and energy-efficient route for biofuel generation. Essentially, ligninolytic white-rot fungi and their enzyme arsenals degrade the plant biomass into structural constituents with minimal by-products generation. Hemi- or cellulolytic enzymes from certain soft and brown-rot fungi are always favoured to hydrolyze complex polysaccharides into fermentable sugars and other value-added products. However, the cost of saccharifying enzymes remains the major limitation, which hinders their application in lignocellulosic biorefinery. In the past, research has been focused on the role of lignocellulolytic fungi in biofuel production; however, a cumulative study comprising the contribution of the lignocellulolytic enzymes in biorefinery technologies is still lagging. Therefore, the overarching goal of this review article is to discuss the major contribution of lignocellulolytic fungi and their enzyme arsenal in global biofuel research and multiproduct biorefinery.

Waste-to-nutrition: a review of current and emerging conversion pathways

Residual biomass is acknowledged as a key sustainable feedstock for the transition towards circular and low fossil carbon economies to supply whether energy, chemical, material and food products or services. The latter is receiving increasing attention, in particular in the perspective of decoupling nutrition from arable land demand. In order to provide a comprehensive overview of the technical possibilities to convert residual biomasses into edible ingredients, we reviewed over 950 scientific and industrial records documenting existing and emerging waste-to-nutrition pathways, involving over 150 different feedstocks here grouped under 10 umbrella categories: (i) wood-related residual biomass, (ii) primary crop residues, (iii) manure, (iv) food waste, (v) sludge and wastewater, (vi) green residual biomass, (vii) slaughterhouse by-products, (viii) agrifood co-products, (ix) C₁ gases and (x) others. The review includes a detailed description of these pathways, as well as the processes they involve. As a result, we proposed four generic building blocks to systematize waste-to-nutrition conversion sequence patterns, namely enhancement, cracking, extraction and bioconversion. We further introduce a multidimensional representation of the biomasses suitability as potential as nutritional sources according to (i) their content in anti-nutritional compounds, (ii) their degree of structural complexity and (iii) their concentration of macro- and micronutrients. Finally, we suggest that the different pathways can be grouped into eight large families of approaches: (i) insect biorefinery, (ii) green biorefinery, (iii) lignocellulosic biorefinery, (iv) non-soluble protein recovery, (v) gas-intermediate biorefinery, (vi) liquid substrate alternative, (vii) solid-substrate fermentation and (viii) more-out-of-slaughterhouse by-products. The proposed framework aims to support future research in waste recovery and valorization within food systems, along with stimulating reflections on the improvement of resources' cascading use.

Culinary and Medicinal Mushrooms: Insight into Growing Technologies

Humans have used mushrooms from the beginning of their history. However, during the last few decades, the market demand for these fruiting bodies has increased significantly owing to the spread in the capabilities of culinary and pharmacological exploitation. Natural mushroom resources have become insufficient to meet the support needs. Therefore, traditional methods of extensive cultivation as well as modern technologies have been exploited to develop effective growing recommendations for dozens of economically important mushroom species. Mushrooms can decompose a wide range of organic materials, including organic waste. They play a fundamental role in nutrient cycling and exchange in the environment. The challenge is a proper substrate composition, including bio-fortified essential elements, and the application of growing conditions to enable a continuous supply of fruiting bodies of market quality and stabilized chemical composition. Many mushroom species are used for food preparation. Moreover, they are treated as functional foods, because they have health benefits beyond their nutritional value, and are used as natural medicines in many countries. Owing to the rapid development of mushroom farming, we reviewed the growing technologies used worldwide for mushroom species developed for food, processing, and pharmacological industries.

The Effects of Fungal Feed Additives in Animals: A Review

As probiotics, fungi enhance animal health and are suitable animal feed additives. In addition to brewing fungi, there are also edible and medicinal fungi. Common fungi utilized in feeding programs include Saccharomyces cerevisiae, Aspergillus oryzae, Pleurotus spp., Antrodia cinnamomea, and Cordyceps militaris. These fungi are rich in glucans, polysaccharides, polyphenols, triterpenes, ergosterol, adenosine, and laccases. These functional components play important roles in antioxidant, anti-inflammatory, anti-obesity, and immune system regulation. As such, fungal feed additives could be of potential use when breeding livestock. In previous studies, fungal feed additives enhanced body weight and egg production in poultry and improved the feed conversion rate. Several mycotoxins can be produced by hazardous fungi but fortunately, the cell walls constituents and enzymes of fungal probiotics can also act to decrease the toxicity of mycotoxins. Overall, fungal feed additives are of value, but their safety and usage must be studied further, including cost-benefit economic analyses.

A diet containing native or fermented wheat bran does not interfere with natural microbiota of laying hens

Wheat bran (WB) is an important side product of the milling industry and can serve as dietary fiber compound for monogastric animals. The aim of this study was to evaluate the influence of native or fermented WB on the gut physiology and microbiology of laying hens. To accomplish this, 24 laying hens were fed the following diets: conventional diet without WB; 15% native WB in the diet; 15% WB fermented with Pleurotus eryngii; and 15% WB fermented with P. eryngii and a lactic acid bacterial culture. Immediately after slaughtering, digesta samples were taken from the jejunum, ileum and cecum, respectively. Total DNA was extracted and subsequently investigated with 16S DNA amplicon sequencing. Neither native nor fermented WB supplementations negatively affected the feed conversion ratio, laying performance or the relative abundances and alpha-diversity of microbiota in the intestine. Effects of WB-based diets on gut morphology were only recognized in the jejunum (reduced villum height and mucosa thickness). Likewise, WB supplementation decreased the digestibility of DM and starch. Based on these findings, it was demonstrated that different WB variants are applicable without exerting practically negative consequences on performance or on gut microbiota. Fermentation improved the digestibility/retention of dietary fat and phosphorus. However, no further beneficial effects were observed. This study also allowed a more in-depth view on the laying hens' gut microbiome and its variation within the gut segments.

Fermented wheat bran by xylanase-producing Bacillus cereus boosts the intestinal microflora of broiler chickens

Wheat bran, while a nutritious and economic feed ingredient, contents high levels of non-starch polysaccharides which entraps nutrients and interferes digestion and absorption. To study the influence of fermented wheat bran by xylanase-producing Bacillus cereus on growth performance and intestinal microflora of broiler chickens, a total of 180 broilers (21-day-old, mixed of male and female) were randomly divided into 3 treatments, with 6 replicates in each treatment and 10 broilers in each replicate: 1) control check (CK), corn-soybean meal-based diet; 2) wheat bran group (WB), 5% of the corn were replaced with wheat bran; and 3) fermented wheat bran group (FWB), 5% of the corn were replaced with fermented wheat bran. Growth performance was determined in the period of 21- to 42-day-old. Intestinal digestive enzyme activities and microbiota diversity were analyzed on day 42. No differences were observed on growth performance among treatments (P > 0.05). The activity of amylase in the duodenum of FWB was 1.56 times higher than CK (P < 0.05). The Chao1 index of microbiota in cecum of FWB increased 24.26% compared with CK (P < 0.01). The amount of Bifidobacteriaceae in cecum of WB was 29.1 times and 15.8 times higher than CK and FWB (P < 0.05) respectively. Principal co-ordinates analysis in cecum revealed the dissimilarity microbiota among treatments. In summary, the use of fermented wheat bran to partially replace corn (5%) in diets had no adverse effect on growth performance and triggered beneficial effects such as increasing duodenal amylase activity and intestinal microflora abundance in broiler chickens. These observations support that solid-state fermentation by xylanase-producing Bacillus cereus is feasible approach to pre-treat wheat bran for feedstuff industry.

Cellulase production by white-rot basidiomycetous fungi: solid-state versus submerged cultivation

White-rot basidiomycetous (WRB) fungi are a group of wood-decaying fungi that are known to be endowed with the ability to secrete enzymes that can catalyze decomposition of a range of plant cell wall polysaccharides, including cellulose and lignin. Expression of these enzymes is induced by the substrate and the enzyme yields obtained depend on the growth of the fungi and thus the mode of cultivation. In order to exploit WRB fungi for local enzyme production for converting lignocellulosic materials in biorefinery processes, the fungi can principally be cultivated in either solid-state (SSC) or submerged cultivation (SmC) systems. In this review, we quantitatively assess the data available in the literature on cellulase production yields by WRB fungi cultivated by SSC or SmC. The review also assesses cellulolytic enzyme production rates and enzyme recovery when WRB fungi are cultivated on different biomass residues in SSC or SmC systems. Although some variation in cellulase production yields have been reported for certain substrates, the analysis convincingly shows that SmC is generally more efficient than SSC for obtaining high cellulase production yields and high cellulase production rates on the substrate used. However, the cultivation method also affects the enzyme activity profile obtained, and the resulting enzyme titers and significant dilution of the enzymes usually occurs in SmC. The review also highlights some future approaches, including sequential cultivations and co-cultivation of WRB fungi for improved enzyme expression, as well as on-site approaches for production of enzyme blends for industrial biomass conversion. The quantitative comparisons made have implications for selection of the most appropriate cultivation method for WRB fungi for attaining maximal cellulase production.