Search Results (210)

The objective of this study was the evaluation of fungal solid-state fermentation (SSF) for the production of alginate lyase and extraction of uronic acids from Sargassum sp. For this purpose, the fungi Trichoderma asperellum, Aspergillus oryzae, and Rhizopus oryzae were applied (alone or combined) to Sargassum sp. biomass through SSF (10⁷ spores g_biomass⁻¹, 30 °C, and 7 days of treatment). In general, individual SSF with all three fungi degraded the biomass, achieving a marked synergy in the production of cellulase, laminarinase, and alginate lyase activities (especially for the last one). Trichoderma was the most efficient species in producing laminarinase, whereas Rhizophus was the best option for producing alginate lyase. However, when dual combinations were tested, the maximal values of alginate lyase activities were reached (13.4 ± 0.2 IU g_biomass⁻¹ for Aspergillus oryzae and Rhizopus oryzae). Remarkably, uronic acids were the main monomeric units from algal biomass solubilization, achieving a maximum yield of 14.4 mg_uronic g_biomass⁻¹, with the A + R condition being a feasible, eco-friendly alternative to chemical extraction of this monomer. Additionally, the application of all the fungal pretreatments drastically decreased the total phenolic content (TPC) in the biomass from 369 mg L⁻¹ to values around 44–84 mg L⁻¹, minimizing the inhibition for possible subsequent biological processes in which the residual solid can be used. Full article

Agriculture and its related industries produce annually a vast amount of byproducts and waste which comprise a large proportion of global waste. Only a small percentage is managed with environmentally acceptable procedures, while a large proportion is either incinerated or discarded into nearby open fields, causing serious environmental burdens. Since these byproducts exhibit a rich nutritional and phytochemical content, they may be considered as raw materials for various industrial applications, initiating the need for the development of sustainable and eco-friendly methods for their valorization. Among the various methods considered, Solid-State Fermentation (SSF) constitutes an intriguing eco-friendly bioprocess, being suitable for water-insoluble mixtures and providing products with improved stability and depleted catabolic suppression. Thus, there are several literature studies highlighting the aspects and efficacy of SSF for improving the nutritional and phytochemical contents of diverse agro-industrial waste. The review herein aspires to summarize these literature results with a special focus on the enhancement of their antioxidant potency. For this purpose, specific keywords were used for searching multiple scientific databases with an emphasis on the most recent studies and higher impact journals. The presented data establish the usefulness and efficacy of the SSF bioprocess to obtain fermentation products with enhanced antioxidant profiles. Full article

Solid-state fermentation (SSF) involves the growth of microorganisms on solid substrates, mimicking natural environments of many species. Due to sustainability concerns, transforming agro-industrial by-products into value-added products through SSF has been increasingly studied. Brewer’s spent grain (BSG), the main by-product of beer production, mostly consists of barley grain husks, making BSG a great support for microorganism cultivation. Although autoclaving remains the standard sterilization and pretreatment method of substrates, electric field technologies and their attendant ohmic heating (OH) have great potential as an alternative technology. In the present work, pretreatment of BSG by OH was explored in SSF with Aspergillus niger to produce commercially valuable enzymes. OH favored the solubilization of phenolic compounds, total protein, and reducing sugars significantly higher than autoclaving. SSF of treated BSG led to the production of lignocellulosic enzymes, with xylanases being the most active, reaching 540 U/g, a 1.5-fold increase in activity compared to autoclaved BSG. Protease activity was also improved 1.6-fold by OH, resulting in 49 U/g. Our findings suggest that OH treatment is an effective alternative to autoclaving and that its integration with SSF is a sustainable strategy to enhance by-product valorization through enzyme production with many industrial applications, according to circular economy guidelines. Full article

Spent coffee grounds (SCG) are a widely available agro-industrial residue rich in carbon and phenolic compounds, presenting significant potential for biotechnological valorization. This study evaluated the use of SCG as a suitable substrate for fungal laccase production and the application of the resulting fermented biomass (RFB), a mixture of fermented SCG and fungal biomass as a biosorbent for textile dye removal. Two fungal strains, namely Lentinus crinitus UCP 1206 and Trametes sp. UCP 1244, were evaluated in both submerged (SmF) and solid-state fermentation (SSF) using SCG. L. crinitus showed superior performance in SSF, reaching 14.62 U/g of laccase activity. Factorial design revealed that a lower SCG amount (5 g) and higher moisture (80%) and temperature (30 °C ± 0.2) favored enzyme production. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analyses confirmed significant structural degradation of SCG after fermentation, especially in SSF. Furthermore, SCG and RFB were chemically activated and evaluated as biosorbents. The activated carbon from SCG (ACSCG) and RFB (ACRFB) exhibited high removal efficiencies for Remazol dyes, comparable to commercial activated carbon. These findings highlight the potential of SCG as a low-cost, sustainable resource for enzyme production and wastewater treatment, contributing to circular bioeconomy strategies. Full article

Spent coffee grounds are the most abundant waste generated during the preparation of coffee beverages, amounting to 60 million tons per year worldwide. Excessive food waste production has become a global issue, emphasizing the need for waste valorization through the bioprocess of solid-state fermentation (SSF) for high added-value compounds. This work aims to identify the operational conditions for optimizing the solid-state fermentation process of spent coffee grounds to recover bioactive compounds (as polyphenols). An SSF process was performed using two filamentous fungi (Trichoderma harzianum and Rhizopus oryzae). An exploratory design based on the Hunter & Hunter method was applied to analyze the effects of key parameters such as inoculum size (spores/mL), humidity (%), and temperature (°C). Subsequently, a Box–Behnken experimental design was carried out to recovery of total polyphenols. DPPH, ABTS, and FRAP assays evaluated antioxidant activity. The maximum concentration of polyphenols was observed in treatment T3 (0.279 ± 0.002 TPC mg/g SCG) using T. harzianum, and a similar result was obtained with R. oryzae in the same treatment (0.250 ± 0.011 TPC mg/g SCG). In the Box–Behnken design, the most efficient treatment for T. harzianum was T12 (0.511 ± 0.017 TPC mg/g SCG), and for R. oryzae, T9 (0.636 ± 0.003 TPC mg/g SCG). These extracts could have applications in the food industry to improve preservation and functionality. Full article

Antinutritional Factors (ANFs) are compounds produced by plants as defense mechanisms, and in high concentrations, they inhibit nutritional properties. Reducing these ANFs increases the presence of proteins, antioxidants, and vitamins, which is crucial for optimizing animal feed, particularly in developing countries where traditional methods may be costly. Solid-state fermentation (SSF) has the potential to improve the nutritional quality of animal feed derived from cereals and legumes cultivated and non-commercially cultivated by reducing antinutrients and enhancing nutrient availability. This review also considers the potential of non-native species, including those exhibiting invasive behavior and taxonomic similarity to cultivated varieties, as alternative substrates for SSF. Additionally, SSF highlights the biological properties of ANFs when extracted and utilized for technological and industrial advancements. Solid-state fermentation with lactic acid bacteria could be an effective and straightforward method for reducing these antinutritional factors while simultaneously enriching protein content. The aim is to present solid-state fermentation as a biotechnological tool to reduce antinutritional factors and enhance the nutritional content of legumes and cereals that are not cultivated for animal feed. This perspective contributes to expanding the range of raw materials considered for SSF by including taxonomically related but underutilized and ecologically problematic plant resources. Full article

The increasing global demand for protein underscores the necessity for sustainable alternatives to soybean-based animal feed, which poses a challenge to human food security. Thus, the search for sustainable, alternative protein sources is transforming the feed industry in its effort to sustainable operations. In this study, a microbial consortium was subjected to adaptive laboratory evolution using non-protein nitrogen (NPN) and wheat straw as the sole carbon source. The evolved microbial consortium was subsequently utilized to perform solid-state fermentation on wheat straw and NPN to produce feed protein. After 20 generations, the microbial consortium demonstrated tolerance to 5 g/L NPN, including ammonium sulfate, ammonium chloride, and urea, which represents a fivefold increase compared to the original microbial consortium. Among the three NPNs tested, the evolved microbial consortium exhibited optimal growth performance with ammonium sulfate. Subsequently, the evolved microbial consortium was employed for the solid-state fermentation (SSF) of wheat straw, and the fermentation conditions were optimized. It was found that the true protein content of wheat straw could be increased from 2.74% to 10.42% under specific conditions: ammoniated wheat straw (15% w/w), non-sterilization of the substrate, an inoculation amount of 15% (v/w), nitrogen addition amount of 0.5% (w/w), an initial moisture content of 70%, a fermentation temperature of 30 °C, and a fermentation duration of 10 days. Finally, the SSF process for wheat straw was successfully scaled up from 0.04 to 2.5 kg, resulting in an increased true protein content of 9.84%. This study provides a promising approach for the production of feed protein from straw and NPN through microbial fermentation, addressing protein resource shortages in animal feed and improving the value of waste straw. Full article

Fungi, including filamentous organisms such as yeasts, play essential roles in various processes such as nutrient exchange in ecosystems, the cultivation of mushrooms, and solid-state fermentation (SSF). SSF involves microbial growth on solid substrates without free water, leading to the production of enzymes, bioactive compounds, and biofuels. This fermentation method offers advantages like lower production costs, reduced waste disposal issues, and the efficient utilization of agricultural residues and fruit and vegetable by-products. Filamentous fungi excel in SSF due to their enzyme secretion capacity and ability to produce valuable compounds. The process is influenced by biological, physico-chemical, and environmental factors, requiring careful optimization for optimal results. Fruit and vegetable by-products are increasingly recognized as valuable substrates for SSF, offering rich sources of bioactive compounds and high nutritional value. The optimization of SSF processes, compatibility with various substrates, and potential for producing diverse value-added products make SSF a promising method for sustainable resource utilization and enhanced product development. Future research should focus on improving process efficiency, expanding the substrate range, enhancing product quality and yield, and integrating SSF with other technologies for enhanced production capabilities. Full article

Solid-state fermentation (SSF) is increasingly applied to enhance the functional properties of traditional herbal medicines. In this study, we investigated the effect of lactic acid bacteria (LAB) and other probiotic strains on the bioactive profile of Radix Angelica gigas (Danggui) during SSF. SSF was carried out by incubating a mixture of the herbal powder and distilled water (1:1, pH 7.0) with LAB strains (Lactobacillus rhamnosus, L. acidophilus, L. buchneri, L. reuteri, L. plantarum) and additional microbes (Bacillus subtilis, Saccharomyces cerevisiae) under controlled conditions. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and total phenolic and flavonoid contents were measured. L. buchneri exhibited the highest growth, with significant proliferation observed on days 4 and 6, especially at 30 °C (p < 0.05). The DPPH and ABTS radical scavenging activities and total phenol and total flavonoid contents were increased by up to 230% (35 °C), 111% (30 °C), 137% (30 °C and 35 °C), and 133% (35 °C), respectively, in fermented herbs compared with those in non-fermented herbs. Antioxidant levels (DPPH, phenol, and flavonoid) exhibited a significant positive correlation with bacterial growth and a significant negative correlation with pH in SSF, but ABTS did not exhibit any statistically significant correlation with bacterial growth or pH. Moreover, multi-strain fermentations involving L. acidophilus and L. plantarum significantly increased the antioxidant activities compared to single-strain fermentations (p < 0.05). These findings suggest that SSF using probiotic LAB can significantly improve the bioactive composition of Radix Angelica gigas, providing a scientific method for modernizing traditional herbal medicine with potential uses in human and animal health. Full article

The valorization of plant biomass is one of the main strategies for sustainable development. However, its use as energy, biofuels, fertilizers, value-added products, or even food is severely affected by the complexity of the plant cell wall. Therefore, the evaluation of fungi with high production of lignocellulolytic enzymes capable of efficiently degrading these substrates constitutes a viable, clean, and eco-friendly solution, allowing, for example, an increase in the digestibility and nutritional quality of alternative animal feed sources. For these reasons, the present study evaluated the ability of the mutant strain Trichodema viride M5-2 to improve the nutritional composition of the forage legumes Lablab purpureus and Mucuna pruriens through solid-state fermentation. Endo- and exoglucanase cellulolytic activity was assessed, as well as the effect of fermentation on the fiber’s physical properties and chemical composition. Molecular changes in the structure of plant fiber were analyzed using infrared spectroscopy. Increased production of the cellulolytic complex of the enzymes endoglucanase (3.29 IU/mL) and exoglucanase (0.64 IU/mL) was achieved in M. pruriens. The chemical composition showed an increase in true protein and a decrease in neutral fiber, hemicellulose, and cellulose, with a consequent improvement in nutritional quality. Fiber degradation was evident in the infrared spectrum with a significant decrease in the signals associated with cellulose and, to a lesser extent, with lignin. It can be concluded that the mutant strain T. viride M5-2 produced chemical, physical, and molecular changes in the fibrous and protein fractions of L. purpureus and M. pruriens through SSF, which improved their nutritional value as an alternative feed for animal nutrition. By promoting the use of this fungus, the nutritional quality of this source is increased through an effective and eco-friendly process, which contributes to mitigating the environmental impact of food production, in accordance with sustainability objectives and the need for more responsible agricultural practices. Full article

This study developed a solid-state fermentation system based on Trichoderma harzianum, which significantly enhanced the nutritional value of distiller’s grain (DG) feed through a multi-stage synergistic treatment process. During the cellulase production phase, rice husk was used as an auxiliary material, and specific degradation of DGs was effectively enhanced. Through optimization using response surface methodology, the optimal enzyme production conditions were determined. The filter paper enzyme activity reached a peak of 1.45 U/gds (enzyme activity per gram of dry substrate) when the moisture content was 53%, the fermentation time was 3 days, and the Tween-80 dosage was 0.015 mL/g (dry weight basis). Under these conditions, the crude enzyme solution was used to hydrolyze DGs. Compared to original DGs, the content of reducing sugars increased by 10.75%. In the stage of protein production, segmented hydrolysis fermentation (SHF) and simultaneous saccharification fermentation (SSF) processes were employed using yeast. The results showed that SSF pathway showed better performance, and the true protein content reached 15.16% after 11 days, an increase of 41.5% compared to the control. Finally, through secondary fermentation regulated by Lactobacillus fermentum, the flavor of the feed was significantly improved. This study innovatively integrated bio-enzymatic hydrolysis and multi-strain synergistic fermentation technologies, providing a novel strategy for the efficient and sustainable production of protein feed based on DGs. Full article

The increasing demand for sustainable dietary options has intensified the development of plant-based meat analogues. Despite growing market availability, these products often fail to replicate conventional meat’s sensory and nutritional properties. Solid-state fermentation (SSF) has emerged as a promising biotechnological approach to enhance the quality of plant-derived protein ingredients. This review summarizes recent findings on the use of SSF in meat analogue production, focusing on microbial strains, substrate selection, and fermentation conditions. The reviewed studies indicate that SSF improves protein digestibility, enhances essential amino acid profiles, reduces anti-nutritional factors, and generates desirable flavour compounds. Furthermore, SSF offers advantages over submerged fermentation in energy and water efficiency, supporting its application in sustainable food processing. The findings highlight SSF’s potential to address key limitations of current meat alternatives and its relevance for developing nutritionally adequate and sensory-appealing products. Integration of SSF into plant-based protein processing may play a critical role in advancing environmentally friendly protein systems. Full article

Flaxseed meal (FSM) is a by-product of flaxseed product production that is wasted unreasonably at present. In this study, we used Bacillus subtilis K6, a dominant microbial strain, for solid-state fermentation (SSF) of FSM following preliminary screening to improve FSM utilization efficiency and enhance the soluble dietary fiber (SDF) content while modifying its functional properties. FSM’s microstructure was characterized before and after fermentation, and the functional properties of the dietary fiber (DF) in the FSM were assessed. Single-factor experiments combined with response surface methodology were conducted to optimize SSF parameters using SDF yield as the response variable. The optimal conditions were determined as follows: 45 h fermentation time, 40.5 °C temperature, and 1:0.65 material-to-liquid ratio. Under these conditions, the SDF yield reached 33.45 ± 0.24%, an SDF yield increase of 36.92%. Scanning electron microscopy and confocal laser scanning microscopy demonstrated FSM’s structural disruption during fermentation. Furthermore, SDF and insoluble DF showed improved water-holding, oil-holding, and swelling capacities following fermentation. These results indicate that SSF effectively enhances the SDF content in FSM and optimizes its functional properties, thereby providing a theoretical foundation for the valorization of flaxseed by-products. Full article

With increasing research, the nutritional value of oats is gaining recognition. Fermentation is an emerging biotransformation pattern that changes the nutritional structure of whole grains. Currently, research on whole-grain fermentation is relatively focused on phenolic compounds and their antioxidants, but less attention has been given to avenanthramides (Avns) and the glycemic index (GI) in fermented oats. In this study, oats were subjected to solid-state fermentation (SSF) by Monascus purpureus for 21 days, and samples were taken at different time points. Changes in the contents of nutrients, phytochemicals, and antinutritional factors were analyzed using one-way ANOVA. Additionally, a simulated in vitro digestion experiment was conducted to assess the estimated glycemic index (eGI) of SSF oats. The results revealed that the nutritional structure of oats was changed by SSF, and the Avns content significantly increased, with 3.2 times more Avns in SSF oats than in unfermented oats, including 3.05, 3.09, 3.09, and 3.7 times more Avn A, Avn B, Avn C, and Avn D, respectively, and the eGI was reduced from 40.22 to 39.97 with increasing fermentation time. In general, SSF with Monascus purpureus has improved nutritional value, significantly increased the content of active ingredients, and reduced the level of eGI and two antinutritional factors (phytate and oxalate), which provides an effective way to improve the nutritional and digestive characteristics of oats. Full article

The overwhelming amount of cassava residues and okara are a foremost challenge for the food processing industry environmental loading. The purpose of this article is to utilize Pleurotus ostreatus mycelium to ferment solid cassava and soybean residue, resulting in mycelial biomass with nutritional values and promising prebiotic activities from fermented waste sources. By blending a ratio of 80% cassava and 20% soybean residues, the mycelium spread rapidly after 3 days of culture, from 1.73 mm on the first day to 13.32 mm on the third day, and completely covered the surface after 9 days of culture (120 mm). Using the solid-state fermentation (SSF) method allowed us to improve the content of substances isolated from mycelium biomass, where polysaccharide content rose by 2.1 times to 3.44 mg/g, and the protein content increased by 1.84 times over the initial substrate. The prebiotic activity of extracted PS was greatest in P. acidilactici NBD8 (1.58); for L. pentosus NH1, L. argentoraten NH15, and L. plantarum WCFS1 strains, the indices were 0.11, 0.17, and 0.3, respectively. The SSF process with P. ostreatus mycelium has the potential to be an effective method for improving the nutrition and digestibility of soybean and cassava residues for application in the production of nature-derived animal feed, as well as contributing to fully utilized agricultural residue, agriculture’s circular economy, reducing environmental issues, and achieving the net-zero carbon emissions target by 2050, as the Vietnam government committed to achieving during the COP26 World Leaders’ Summit in 2021. Full article