Biomass, lignocellulolytic enzyme production and lignocellulose degradation patterns by Auricularia auricula during solid state fermentation of corn stalk residues under different pretreatments

Metabolite profiling, antioxidant and anti-glycemic activities of Tartary buckwheat processed by solid-state fermentation(SSF)with Ganoderma lucidum

The aim of this study was to investigate the effect of Ganoderma lucidum fermentation on antioxidant and anti-glycemic activities of Tartary buckwheat. Xylanase, total cellulase (CMCase and FPase) and β-glucosidase in fermented Tartary buckwheat (FB) increased significantly to 242.06 U/g, 17.99 U/g and 8.67 U/g, respectively. And the polysaccharides, total phenols, flavonoids and triterpenoids, which is increased by 122.19%, 113.70%, 203.74%, and 123.27%, respectively. Metabolite differences between non-fermented Tartary buckwheat (NFB) and FB pointed out that 445 metabolites were substantially different, and were involved in related biological metabolic pathways. There was a considerable rise in the concentrations of hesperidin, xanthotoxol and quercetin 3-O-malonylglucoside by 240.21, 136.94 and 100.77 times (in Fold Change), respectively. The results showed that fermentation significantly increased the antioxidant and anti-glycemic activities of buckwheat. This study demonstrates that the fermentation of Ganoderma lucidum provides a new idea to enhance the health-promoting components and bioactivities of Tartary buckwheat.

Bidirectional Solid-State Fermentation of Highland Barley by Edible Fungi to Improve Its Functional Components, Antioxidant Activity and Texture Characteristics

In food industry, the characteristics of food substrate could be improved through its bidirectional solid-state fermentation (BSF) by fungi, because the functional components were produced during BSF. Six edible fungi were selected for BSF to study their effects on highland barley properties, such as functional components, antioxidant activity, and texture characteristics. After BSF, the triterpenes content in Ganoderma lucidum and Ganoderma leucocontextum samples increased by 76.57 and 205.98%, respectively, and the flavonoids content increased by 62.40% (Phellinus igniarius). Protein content in all tests increased significantly, with a maximal increase of 406.11% (P. igniarius). Proportion of indispensable amino acids increased significantly, with the maximum increase of 28.22%. Lysine content increased largest by 437.34% to 3.310 mg/g (Flammulina velutipes). For antioxidant activity, ABTS radical scavenging activity showed the maximal improvement, with an increase of 1268.95%. Low-field NMR results indicated a changed water status of highland barley after fermentation, which could result in changes in texture characteristics of highland barley. Texture analysis showed that the hardness and chewiness of the fermented product decreased markedly especially in Ganoderma lucidum sample with a decrease of 77.96% and 58.60%, respectively. The decrease indicated a significant improvement in the taste of highland barley. The results showed that BSF is an effective technology to increase the quality of highland barley and provide a new direction for the production of functional foods.

Necessity of Different Lignocellulose on Exopolysaccharide Synthesis and Its Hypoglycemic Activity In Vitro of Inonotus obliquus

Current work proposes elm sawdust, poplar sawdust, pine sawdust, and cotton straw with different lignocellulose compositions and structures as the research objects to investigate the relationship between the hypoglycemic activity of mycelium polysaccharides from Inonotus obliquus and lignocellulose biodegradation. Four kinds of lignocellulosic materials could significantly increase the exopolysaccharide content and α-glucosidase inhibition rate and advance the occurrence time of α-glucosidase inhibition activity. Among all groups, the polysaccharide synthesis promotion effect of the cotton straw group was the best, which exopolysaccharide yield was 92.05% higher than that of the control group after 11-day fermentation. Meanwhile, the highest α-glucosidase inhibitory activity was found in the elm sawdust group on the 11th day (30.99%, which was 137.47% higher than control), and the exopolysaccharide in the elm sawdust group showed its effectiveness on glucose consumption of insulin resistant HepG2 cells at the concentration of 20 µg/mL, significantly higher than that of the metformin group (P < 0.05). The cellulose in the non-crystalline region of elm and pine and the hemicellulose of poplar were mainly used in the fermentation of I. obliquus, while the cellulose in the crystalline zone and amorphous zone of cotton straw was degraded to improve the exopolysaccharide content of I. obliquus. This paper revealed the necessity of different kinds of lignocellulose for the synthesis of active polysaccharide from I. obliquus and provided a new idea for the regulation of polysaccharide synthesis pathway.

Synchronous reducing anti-nutritional factors and enhancing biological activity of soybean by the fermentation of edible fungus Auricularia auricula

Auricularia auricula fermentation was performed to reduce anti-nutritional factors, improve nutritional components, and enhance biological activity of soybean. Results showed that the contents of raffinose, stachyose, and trypsin inhibitor were significantly decreased from initial 1.65 g L-1, 1.60 g L-1, and 284.67 μg g-1 to 0.14 g L-1, 0.35 g L-1, and 4.52 μg g-1 after 144 h of fermentation, respectively. Simultaneously, the contents of polysaccharide, total phenolics, and total flavonoids were increased, and melanin was secreted. The isoflavone glycosides were converted to their aglycones, and the contents of glyctin and genistin were decreased from initial 1107.99 μg g-1 and 2852.26 μg g-1 to non-detection after 72 h of fermentation, respectively. After 96 h of fermentation, the IC50 values of samples against DPPH and ABTS radicals scavenging were decreased from 17.61 mg mL-1 and 3.43 mg mL-1 to 4.63 mg mL-1 and 0.89 mg mL-1, and those of samples inhibiting α-glucosidase and angiotensin I-converting enzyme were decreased from 53.89 mg mL-1 and 11.27 mg mL-1 to 18.24 mg mL-1 and 6.78 mg mL-1, respectively, indicating the significant increase in these bioactivities. These results suggested A. auricula fermentation can enhance the nutritional quality and biological activity of soybean, and the fermented soybean products have the potential to be processed into health foods/food additives.

Bioprocess optimization for food-grade cellulolytic enzyme production from sorghum waste in a novel solid-state fermentation bioreactor for enhanced apple juice clarification

Transforming global agricultural waste into eco-friendly products like industrial enzymes through bioconversion can help address sustainability challenges aligning with the United Nations' Sustainable Development Goals. Present study explored the production of high-yield food-grade cellulolytic enzymes from Trichoderma reesei MTCC 4876, using a novel media formulation with a combination of waste sorghum grass and cottonseed oil cake (3:1). Optimization of physical and environmental parameters, along with the screening and optimization of media components, led to an upscaled process in a novel 6-L solid-state fermentation (SSF)-packed bed reactor (PBR) with a substrate loading of 200 g. Saturated forced aeration proved crucial, resulting in high fungal biomass (31.15 ± 0.63 mg glucosamine/gm dry fermented substrate) and high yield cellulase (20.64 ± 0.36 FPU/g-ds) and xylanase (16,186 ± 912 IU/g-ds) production at an optimal airflow rate of 0.75 LPM. The PBR exhibited higher productivity than shake flasks for all the enzyme systems. Microfiltration and ultrafiltration of the crude cellulolytic extract achieved 94% and 71% recovery, respectively, with 13.54 FPU/mL activity in the cellulolytic enzyme concentrate. The concentrate displayed stability across wide pH and temperature ranges, with a half-life of 24.5-h at 50 °C. The cellulase concentrate, validated for food-grade safety, complies with permissible limits for potential pathogens, heavy metals, mycotoxins, and pesticide residue. It significantly improved apple juice clarity (94.37 T%) by reducing turbidity (21%) and viscosity (99%) while increasing total reducing sugar release by 63% compared with untreated juice. The study also highlighted the potential use of lignin-rich fermented end residue for fuel pellets within permissible SOx emission limits, offering sustainable biorefinery prospects. Utilizing agro wastes in a controlled bioreactor environment underscores the potential for efficient large-scale cellulase production, enabling integration into food-grade applications and presenting economic benefits to fruit juice industries.

Trends in the development and current perspective of thermostable bacterial hemicellulases with their industrial endeavors: A review

Hemicellulases are enzymes that hydrolyze hemicelluloses, common polysaccharides in nature. Thermophilic hemicellulases, derived from microbial strains, are extensively studied as natural biofuel sources due to the complex structure of hemicelluloses. Recent research aims to elucidate the catalytic principles, mechanisms and specificity of hemicellulases through investigations into their high-temperature stability and structural features, which have applications in biotechnology and industry. This review article targets to serve as a comprehensive resource, highlighting the significant progress in the field and emphasizing the vital role of thermophilic hemicellulases in eco-friendly catalysis. The primary goal is to improve the reliability of hemicellulase enzymes obtained from thermophilic bacterial strains. Additionally, with their ability to break down lignocellulosic materials, hemicellulases hold immense potential for biofuel production. Despite their potential, the commercial viability is hindered by their high enzyme costs, necessitating the development of efficient bioprocesses involving waste pretreatment with microbial consortia to overcome this challenge.

Corn straw-saccharification fiber improved the reproductive performance of sows in the late gestation and lactation via lipid metabolism

With the development of animal husbandry, the shortage of animal feedstuffs has become serious. Dietary fiber plays a crucial role in regulating animal health and production performance. The aim of this study was to investigate the effects of three kinds of corn straw-saccharification fibers (CSSF) such as high-fiber and low-saccharification (HFLS), medium-fiber and medium-saccharification (MFMS), low-fiber and high-saccharification (LFHS) CSSF on the reproductive performance of sows. Thirty-two primiparous Yorkshire sows were randomly assigned to 4 groups, 8 sows for each group. Group A was the basal diet as the control group; groups B - D were added with 6% HFLSCSSF, 6% MFMSCSSF and 6% LFHSCSSF to replace some parts of corn meal and wheat bran in the basal diet, respectively. The experimental period was from day 85 of gestation to the end of lactation (day 25 post-farrowing). The results showed that 6% LFHSCSSF addition significantly increased number of total born (alive) piglets, litter weight at birth (p < 0.05), whereas three kinds of CSSF significantly decreased backfat thickness of sows during gestation (p < 0.001), compared with the control group. Furthermore, CSSF improved the digestibility of crude protein, ether extract and fiber for sows. In addition, the levels of total cholesterol, total triglycerides, and high-density lipoprotein cholesterol in serum of sows were decreased by different kinds of CSSF. Further analysis revealed that CSSF regulated lipid metabolism through adjusting the serum metabolites such as 4-pyridoxic acid, phosphatidyl cholines and L-tyrosine. In summary, CSSF addition to the diets of sows during late gestation and lactation regulated lipid metabolism and improved reproductive performance of sows. This study provided a theoretical basis for the application of corn straw in sow diets.

Improving Enzymatic Saccharification of Peach Palm (Bactris gasipaes) Wastes via Biological Pretreatment with Pleurotus ostreatus

The white-rot fungus Pleurotus ostreatus was used for biological pretreatment of peach palm (Bactris gasipaes) lignocellulosic wastes. Non-treated and treated B. gasipaes inner sheaths and peel were submitted to hydrolysis using a commercial cellulase preparation from T. reesei. The amounts of total reducing sugars and glucose obtained from the 30 d-pretreated inner sheaths were seven and five times higher, respectively, than those obtained from the inner sheaths without pretreatment. No such improvement was found, however, in the pretreated B. gasipaes peels. Scanning electronic microscopy of the lignocellulosic fibers was performed to verify the structural changes caused by the biological pretreatments. Upon the biological pretreatment, the lignocellulosic structures of the inner sheaths were substantially modified, making them less ordered. The main features of the modifications were the detachment of the fibers, cell wall collapse and, in several cases, the formation of pores in the cell wall surfaces. The peel lignocellulosic fibers showed more ordered fibrils and no modification was observed after pre-treatment. In conclusion, a seven-fold increase in the enzymatic saccharification of the Bactris gasipaes inner sheath was observed after pre-treatment, while no improvement in enzymatic saccharification was observed in the B. gasipaes peel.

Active polysaccharides from Lentinula edodes and Pleurotus ostreatus by addition of corn straw and xylosma sawdust through solid-state fermentation

In this study, Lentinula edodes and Pleurotus ostreatus were selected as representatives to explore the effects of corn straw and xylosma sawdust on the production and activity of polysaccharides by edible fungi during solid-state fermentation. The results clearly indicated that the addition of lignocellulose could promote the polysaccharide content compared to the control group. Meanwhile, the hydroxyl radical scavenging activity of polysaccharides reached the maximum when the glucose concentration was 1.5 %, and among them, the xylosma sawdust groups for two fungi (L. edodes-32.37 %, P. ostreatus-25.86 %) both performed better than corn straw groups (L. edodes-24.96 %, P. ostreatus-20.80 %). In addition, structural characterization and degradation mode analysis were carried out. The results showed that the structure of the xylosma had a stronger destruction than corn straw. The activities of lignocellulolytic enzymes such as carboxymethyl cellulase, filter paper enzyme, β-glucosidase and xylanase increased rapidly in the early stage of fermentation, which could degrade the cellulose and hemicellulose as raw materials for the synthesis of active polysaccharides.

Lignocellulolytic Biocatalysts: The Main Players Involved in Multiple Biotechnological Processes for Biomass Valorization

Human population growth, industrialization, and globalization have caused several pressures on the planet's natural resources, culminating in the severe climate and environmental crisis which we are facing. Aiming to remedy and mitigate the impact of human activities on the environment, the use of lignocellulolytic enzymes for biofuel production, food, bioremediation, and other various industries, is presented as a more sustainable alternative. These enzymes are characterized as a group of enzymes capable of breaking down lignocellulosic biomass into its different monomer units, making it accessible for bioconversion into various products and applications in the most diverse industries. Among all the organisms that produce lignocellulolytic enzymes, microorganisms are seen as the primary sources for obtaining them. Therefore, this review proposes to discuss the fundamental aspects of the enzymes forming lignocellulolytic systems and the main microorganisms used to obtain them. In addition, different possible industrial applications for these enzymes will be discussed, as well as information about their production modes and considerations about recent advances and future perspectives in research in pursuit of expanding lignocellulolytic enzyme uses at an industrial scale.

Full Exploitation of Peach Palm (Bactris gasipaes Kunth): State of the Art and Perspectives

The peach palm (Bactris gasipaes Kunth) is a palm tree native to the Amazon region, with plantations expanding to the Brazilian Southwest and South regions. This work is a critical review of historical, botanical, social, environmental, and nutritional aspects of edible and nonedible parts of the plant. In Brazil, the importance of the cultivation of B. gasipaes to produce palm heart has grown considerably, due to its advantages in relation to other palm species, such as precocity, rusticity and tillering. The last one is especially important, as it makes the exploitation of peach palm hearts, contrary to what happens with other palm tree species, a non-predatory practice. Of special interest are the recent efforts aiming at the valorization of the fruit as a source of carotenoids and starch. Further developments indicate that the B. gasipaes lignocellulosic wastes hold great potential for being upcycled into valuable biotechnological products such as prebiotics, enzymes, cellulose nanofibrils and high fiber flours. Clean technologies are protagonists of the recovery processes, ensuring the closure of the product's life cycle in a "green" way. Future research should focus on expanding and making the recovery processes economically viable, which would be of great importance for stimulating the peach palm production chain.

Screening of cellulose-degrading yeast and evaluation of its potential for degradation of coconut oil cake

Coconut oil cake (COC), a byproduct of oil extraction, contains high levels of cellulose. The aim of this study was to isolate a cellulose-degrading yeast from rotten dahlia that can effectively use COC as the only carbon source for cellulase secretion. Based on screening, Meyerozyma guillermondii CBS 2030 (M. guillermondii) was identified as a potential candidate, with the highest cellulolytic activity among the yeast strains isolated, with the carboxymethyl cellulase (CMCase) activity reaching 102.96 U/mL on day 5. The cellulose in COC samples was evaluated before and after degradation by M. guillermondii. Analysis based on field emission scanning electron microscopy (FESEM) revealed that the COC structure was changed significantly during the treatment, indicating effective hydrolysis. Fourier transform infrared spectroscopy (FTIR) of the modified functional groups indicated successful depolymerization of coconut cake. X-ray diffraction (XRD) and analysis of color differences established effective degradation of COC by M. guillermondii. The results demonstrate that M. guillermondii effectively secretes CMCase and degrades cellulose, which has important practical significance in COC degradation.

Inhibitor formation and detoxification during lignocellulose biorefinery: A review

For lignocellulose biorefinery, pretreatment is needed to maximize the cellulose accessibility, frequently generating excess inhibitory substances to decline the efficiency of the subsequent fermentation processes. This mini-review updates the current research efforts to detoxify the adverse impacts of generated inhibitors on the performance of biomass biorefinery. The lignocellulose pretreatment processes are first reviewed. The generation of inhibitors, furans, furfural, phenols, formic acid, and acetic acid, from the lignocellulose, with their action mechanisms, are listed. Then the detoxification processes are reviewed, from which the biological detoxification processes are noted as promising and worth further study. The challenges and prospects for applying biological detoxification in lignocellulose biorefinery are outlined. Integrated studies considering the entire biorefinery should be performed on a case-by-case basis.