Substrate In Solid State Fermentation Research Articles

Solid-state fermentation using wheat bran to produce glucose syrup and functional cereal bars.

Wheat bran is one of the most abundant by-products from grain milling, which can be used as substrate for solid-state fermentation (SSF) to obtain enzymes able to convert this agro-industrial waste into glucose syrup, which in turn can be applied for the production of different food products. The present study aimed to determine centesimal composition of wheat bran, obtain enzymatic extract that converts wheat bran into wheat glucose syrup (WGS), produce rice flakes cereal bars (RFCB), and evaluate their nutritional composition and the presence of functional compounds, as well as their antioxidant potential. Determination of centesimal composition of wheat bran demonstrated its nutritional potential. Enzymatic extract was obtained and it converted wheat bran into WGS, which were applied to rice flakes producing RFCB. These cereal bars proved to be a source of dietary fiber (1.8g) and soluble protein (7.2g) while RCFB produced with corn glucose syrup did not present these nutritional components. In addition, RFCB produced with WGS showed polyphenolic compounds, among them flavonoids, which exhibited antioxidant activity by DPPH and ABTS radical scavenging (47.46% and 711.89μM Trolox Equivalent/g, respectively), and iron ion reduction (71.70μM Trolox equivalent/g). Final product showed a decrease in caloric value and sodium content. Therefore, the present study showed that the bioprocess of SSF yields a nutritional, ecological, and functional food product, which might be of great interest for food industry, adding nutritional and functional value to a well-stablished product.

Production, characterization and application of polygalacturonase produced by Lentinus tigrinus CCMB 553

Polygalacturonases can be used to improve the processing of fruit juices and wines. This study aimed to produce, characterize and evaluate the potential application of polygalacturonase obtained from Lentinus tigrinus CCMB 553 in mango juice clarification. The fungal was isolated from the northeastern semi-arid region and fermented using Passiflora cincinnata bark as a substrate for solid state fermentation. The optimal conditions for enzyme production were obtained by applying the three-level factorial experimental design and were defined as 9 days and 30 °C for time and temperature, respectively. The optimal pH and temperature were determined by applying the Doehlert design and the results showed higher production between 45 and 60 °C and 4.0 and 5.5 for temperature and pH respectively. Km and Vmax of polygalacturonase from Lentinus tigrinus were 2.7 mg/mL and 12.86 μmol/min. The enzyme maintained 40 % residual activity after 30 min at 80 C. The influence of cations on enzyme activity was studied, and calcium ions seem to have a positive influence on enzyme activity, while Fe2+ ions have a negative influence. K+, Na+ and NH4+ salts showed little influence on the polygalacturonase activity of Lentinus tigrinus. The application in the clarification of mango juice (Mangifera indica) using optimal conditions obtained resulted in a reduction of 45% of the viscosity and the clarification by about 79%. The results show that the polygalacturonase produced by Lentinus tigrinus CCMB 553 was efficiently applied in mango juice, improving the quality of the juice.

Performance evaluation of Trichoderma reseei in tolerance and biodegradation of diuron herbicide in agar plate, liquid culture and solid-state fermentation.

The present study evaluated the performance of the fungus Trichoderma reesei to tolerate and biodegrade the herbicide diuron in its agrochemical presentation in agar plates, liquid culture, and solid-state fermentation. The tolerance of T. reesei to diuron was characterized through a non-competitive inhibition model of the fungal radial growth on the PDA agar plate and growth in liquid culture with glucose and ammonium nitrate, showing a higher tolerance to diuron on the PDA agar plate (inhibition constant 98.63 mg L-1) than in liquid culture (inhibition constant 39.4 mg L-1). Diuron biodegradation by T. reesei was characterized through model inhibition by the substrate on agar plate and liquid culture. In liquid culture, the fungus biotransformed diuron into 3,4-dichloroaniline using the amide group from the diuron structure as a carbon and nitrogen source, yielding 0.154mg of biomass per mg of diuron. A mixture of barley straw and agrolite was used as the support and substrate for solid-state fermentation. The diuron removal percentage in solid-state fermentation was fitted by non-multiple linear regression to a parabolic surface response model and reached the higher removal (97.26%) with a specific aeration rate of 1.0 vkgm and inoculum of 2.6 × 108 spores g-1. The diuron removal in solid-state fermentation by sorption on barley straw and agrolite was discarded compared to the removal magnitude of the biosorption and biodegradation mechanisms of Trichoderma reesei. The findings in this work about the tolerance and capability of Trichoderma reesei to remove diuron in liquid and solid culture media demonstrate the potential of the fungus to be implemented in bioremediation technologies of herbicide-polluted sites.

Optimization and characterization of laccase (LccH) produced by Hexagonia hirta MSF2 in solid-state fermentation using coir pith wastes (CPW)

The accumulation of coir pith waste, a byproduct of coconut husk processing, poses environmental and logistical challenges. An innovative and sustainable solution involves using coir pith as a substrate for solid-state fermentation (SSF). In SSF, coir pith can be converted into valuable products, such as enzymes, organic acids, and bioactive compounds. The present study aimed to evaluate laccase production by Hexagonia hirta MSF2 through SSF using the coir pith waste as substrate. Physico-chemical parameters like moisture, pH, temperature, C source, N source, and CuSO4 concentrations were pre-optimized, and optimized through RSM. Laccase activity of 1585.24 U g−1 of dry substrate was recorded by H. hirta MSF2 on coir pith containing 1 % C source, 0.5 % N source, 0.25 mM of CuSO4 concentration, moisture content of 75 % at pH 4.6 and temperature 28 °C. Subsequently, the enzyme extraction parameters including, extraction buffer, mode of extraction, and temperature were optimized. The molecular weight of laccase was 66 kDa as observed by SDS-PAGE and native-PAGE. The optimum activity of partially purified laccase was achieved at 40 °C, and pH 4.0. Increasing salt concentration and use of different inhibitors affected the laccase activity. Organic solvents like dimethyl sulphoxide (DMSO) and methanol, and metal ions like BaCl2, CaCl2, CuSO4, and MnCl2 stimulated the laccase activity. Hence, coir pith used in SSF offers a dual benefit of waste management and enzyme synthesis through an eco-friendly and cost-effective approach.

Rice Husk, Brewer's Spent Grain, and Vine Shoot Trimmings as Raw Materials for Sustainable Enzyme Production.

Solid by-products with lignocellulosic structures are considered appropriate substrates for solid-state fermentation (SSF) to produce enzymes with diverse industrial applications. In this work, brewer's spent grain (BSG), rice husk (RH), and vine shoot trimmings (VSTs) were employed as substrates in SSF with Aspergillus niger CECT 2088 to produce cellulases, xylanases, and amylases. The addition of 2% (NH4)2SO4 and 1% K2HPO4 to by-products had a positive effect on enzyme production. Substrate particle size influenced enzyme activity and the overall highest activities were achieved at the largest particle size (10 mm) of BSG and RH and a size of 4 mm for VSTs. Optimal substrate composition was predicted using a simplex centroid mixture design. The highest activities were obtained using 100% BSG for β-glucosidase (363 U/g) and endo-1,4-β-glucanase (189 U/g), 87% BSG and 13% RH for xylanase (627 U/g), and 72% BSG and 28% RH for amylase (263 U/g). Besides the optimal values found, mixtures of BSG with RH or VSTs proved to be alternative substrates to BSG alone. These findings demonstrate that SSF bioprocessing of BSG individually or in mixtures with RH and VSTs is an efficient and sustainable strategy to produce enzymes of significant industrial interest within the circular economy guidelines.

Biotransformation of Raw Mango Seed Waste into Bacterial Hydrolytic Enzymes Enhancement Via Solid State Fermentation Strategy.

Solid waste generation is a huge contributor to environmental pollution issues, and food wastes are prominent in this category due to their large generation on a day-to-day basis. Thus, the settlement of daily food waste is one of the major constraints and needs innovative manufacturingsheme to valorize solid waste insustainable manner. Moreover,these food wastes are rich in organic content, which has promising scope for their value-added products. In the present study, raw mango seed waste has been biotransformed to produce bacterial hydrolytic enzymes as feedstock. On investigating the impact of substrate, the highest bacterial cellulase production was recorded to be 18IU/gds FP (filter paper) in 24h of microbial incubation at 5g of substrate in solid-state fermentation (SSF). Furthermore, at 40°C and pH 6.0, 23IU/gds FP enzyme could be produced in 24h of SSF. Beside this, on comparing the influence of inorganic and organic nitrogen sources, urea has been found to provide better cellulase production, which yielded 28IU/gds FP in 24h of incubation, along with 77IU/gds BG (β-glucosidase) and 89IU/gds EG (endoglucanase). On the other hand, Tween-40 and Tween-80, two different surfactants, were employed at a 1.0% concentration for 24h of incubation. It was noticed that Tween-80 showed complete enzyme activity at 24h, which was found to be relatively superior to that of Tween-40. This study may have potential utility in enzyme production using mango seed as a food waste for various industrial applications.

Valorization of Prickly Pear Peel Residues (Opuntia ficus-indica) Using Solid-State Fermentation.

Prickly pear peel (Opuntia ficus-indica) residues can be used as a substrate in solid-state fermentation to obtain bioactive compounds. The kinetic growth of some Aspergillus strains was evaluated. A Box-Hunter and Hunter design to evaluate the independent factors was used. These factors were temperature (°C), inoculum (spores/g), humidity (%), pH, NaNO3 (g/L), MgSO4 (g/L), KCl (g/L), and KH2PO4 (g/L). The response factors were the amount of hydrolyzable and condensed tannins. The antioxidant and antimicrobial activity of fermentation extracts was evaluated. Aspergillus niger strains GH1 and HT3 were the best for accumulating tannins. The humidity, inoculum, and temperature affect the release of hydrolyzable and condensed tannins. Treatment 13 (low values for temperature, inoculum, NaNO3, MgSO4; and high values for humidity, pH, KCl, KH2PO4) resulted in 32.9 mg/g of condensed tannins being obtained; while treatment 16 (high values for all the factors evaluated) resulted in 3.5 mg/g of hydrolyzable tannins being obtained. In addition, the fermented extracts showed higher antioxidant activity compared to the unfermented extracts. Treatments 13 and 16 showed low inhibition of E. coli, Alternaria sp., and Botrytis spp. The solid-state fermentation process involving prickly pear peel residues favors the accumulation of condensed and hydrolyzable tannins, with antioxidant and antifungal activity.

Effects of pomelo sponge fermented by Monascus ruber on cholesterol metabolism and intestinal microbiota in high-fat diet mice

The purpose of this study is to produce Monascus ruber fermented pomelo sponge products (MFPS) utilizing low-cost pomelo sponge as a solid-state fermentation substrate, and to investigate the effects of MFPS on cholesterol metabolism and gut microbiota in mice. The study of oral MFPS treatment in high-fat diet mice uncovered that a high dosage of MFPS effectively inhibited the increase of body weight, reduced the accumulation of liver and epididymal fat and improved blood cholesterol metabolism in mice. Interestingly, MFPS consumption enhanced the liver's antioxidant capacity, cleared free radicals. Furthermore, HE staining demonstrated that MFPS effectively repaired liver damage. UPLC-QTOF/MS analysis of liver metabolomics revealed that MFPS intervention exerts a substantial regulatory impact on metabolic pathways encompassing alanine, aspartate and glutamate metabolism, biosynthesis of unsaturated fatty acids, steroid hormone biosynthesis, tryptophan metabolism, glycerophospholipid metabolism, fatty acid degradation, folate biosynthesis, etc. High-throughput sequencing of 16S rRNA unveiled that MFPS mitigated the intestinal microbiota imbalance triggered by a high-fat diet, increasing the abundance of probiotics in the intestine, including Lactobacillus and Bifidobacterium. Therefore, these findings demonstrate that MFPS can improve abnormal cholesterol metabolism and balance intestinal flora, offering valuable insights for developing natural and effective cholesterol-lowering products.

Saccharification of Agricultural Wastes and Clarification of Orange Juice by Penicillium rolfsii CCMB 714 Pectinase

Pectinases are enzymes used in several industrial processes. Seven agroindustrial wastes—jackfruit seed meal (Artocarpus heterophyllus), cocoa seed peel (Theobroma cacao), cocoa husks (Theobroma cacao), passion fruit husks (Passiflora edulis), mangosteen husks (Garcinia mangostana), malt residue (Hordeum vulgare) and the peach palm waste (Bactris gasipaes Kunth.)—were evaluated to produce a crude extract containing pectinase activity by Penicillium rolfsii CCMB 714. The jackfruit seed meal was chosen as the best substrate for solid-state fermentation, which was optimized with 4 mL of water as a wetting agent for 2 days at 35 °C and with a 0.5% nitrogen source, whereby the pectinase production increased by 44% (362.09 U/g). The obtained crude extract was characterized and applied to wastes saccharification and orange juice clarification. The pectinase showed better activity at a pH of 3.0 to 5.0 and 55 °C, it stably maintained over 80% of activity at 30–50 °C for up to 60 min and 1 mM CuSO4 increased the pectinase activity by 17%. The saccharification of agroindustrial wastes (cocoa husks, mangosteen husks and passion fruit husks) resulted in 126.55 µmol/mL of reducing sugars from passion fruit husks, which represents an increase of 126% after optimization (45 °C for 22 h). For the clarification of orange juice, it was possible to reduce the absorbance of the juice by 55%. These results elucidate the potential of the low-cost pectinase solution from P. rolfsii CCMB 714 cultivated in jackfruit seed meal for both the enzymatic pretreatment of plant biomass and the application in beverage industries.

Comparative analysis of different rice substrates for solid-state fermentation by a citrinin-free Monascus purpureus mutant strain with high pigment production

Monascus pigment (MP) is a safe and natural microbial coloring agent. MP and red yeast rice (RYR) play an important role in the food industry. In this study, a citrinin-free Monascus puprureus MS-12 with high MP production was generated using dual mutagenesis of atmospheric and room-temperature plasma and heavy ion beam irradiation. The fermentation characteristics of eight rice substrates for solid-state fermentation (SSF) were compared to produce a premium RYR. Indica rice was the optimal fermentation substrate (MP = 4526 U/g in RYR), followed by japonica rice (MP = 3556 U/g). The MP value was <1000 U/g using other substrates (red, brown and black rice) for fermentation. RT-qPCR results demonstrated that the expression levels of MP synthesis- and the glycolysis-related genes of the mutant strain were upregulated compared with those of the parental strain, with MpigA exhibiting a 1.70-fold increase, while the relative expression levels of citrinin synthesis-related genes were downregulated; citE was downregulated 7.84-fold. In comparison to M. purpureus MS-12 mRNA levels using indica rice as the fermentation substrate during SSF, genes for MP, citrinin biosynthesis, and glycolysis resulted in the downregulation of other substrates. Our results show that colored and glutinous rice are unsuitable for RYR preparation via SSF. The maximum MP value was obtained using indical rice as the fermentation substrate, resulting from the upregulated expression levels of the pigment biosynthesis gene cluster and glycolytic pathway.

Characterization of Detergent-Compatible Lipases from Candida albicans and Acremonium sclerotigenum under Solid-State Fermentation.

The purpose of this study was to compare and explore the potential of two distinct lipases at industrial levels after their production using wheat bran substrate in solid-state fermentation. Lipases from Candida albicans (C. albicans) and Acremonium sclerotigenum (A. sclerotigenum) were characterized to assess their compatibility and suitability for use in laundry detergents. The effects of pH, temperature, metal ions, inhibitors, organic solvents, and various commercially available detergents on these lipases were studied in order to compare their activity and stability profiles and check their stain removal ability. Both lipases remained stable across the wide pH (7-10) and temperature (30-50 °C) ranges. C. albicans lipase exhibited optimum activity (51.66 U/mL) at pH 7.0 and 37 °C, while A. sclerotigenum lipase showed optimum activity (52.12 U/mL) at pH 8.0 and 40 °C. The addition of Ca2+ and Mg2+ ions enhanced their activities, while sodium dodecyl sulfate (SDS) and ethylenediamine tetraacetic acid (EDTA) reduced their activities. Lipase from both strains showed tolerance to various organic solvents and considerable stability and compatibility with commercially available laundry detergents (>50%); however, A. sclerotigenum lipase performed slightly better. Characterization of these crude lipases showed nearly 60% relative activity after incubation for 2 h in various detergents, thus suggesting their potential to be employed in the formulation of laundry detergents with easy and efficient enzyme production. The production of thermostable and alkaline lipases from both strains makes them an attractive option for economic gain by lowering the amount of detergent to be used, thus reducing the chemical burden on the environment.

Improving statins production: From non-genetic strategies to genetic strategies.

Statins are lipid-lowering drugs that selectively inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, effectively reducing cholesterol synthesis. With improved nutritional conditions, the demand for statins is increasing in the global market. The use of microbial cell factories for statin biosynthesis has become advantageous due to the rapid advancements in biotechnology. These approaches offer simple operation and easy separation of products. This review provides an overview the strategies for statins production via microbial cell factories, including both traditional fermentation culture (non-genetic) and modern synthetic biology manufacture (genetic). Firstly, the complex fermentation parameters and process control technology on submerged fermentation (SmF) and solid-state fermentation (SSF) are introduced in detail. The potential use of recoverable agricultural wastes/(biomass) as a fermentation substrate in SSF for statin production is emphasized. Additionally, metabolic engineering strategies for constructing robust engineering strains and directed evolution are also discussed. The review highlights the potential and challenges of using microbial cell factories for statin production, and aims to promote greener production modes for statins.

Optimization of solid-state fermentation for enhanced production of pectinolytic complex by Aspergillus tubingensis FAT43 and its application in fruit juice processing.

The main goal of this study was to examine the efficiency of a newly isolated fungus from quince, Aspergillus tubingensis FAT43, to produce the pectinolytic complex using agricultural and industrial waste as the substrate for solid state fermentation. Sugar beet pulp was the most effective substrate inducer of pectinolytic complex synthesis out of all the waste residues examined. For endo-pectinolytic and total pectinolytic activity, respectively, statistical optimization using Placked-Burman Design and Optimal (Custom) Design increased production by 2.22 and 2.15-fold, respectively. Liquification, clarification, and an increase in the amount of reducing sugar in fruit juices (apple, banana, apricot, orange, and quince) processed with pectinolytic complex were identified. Enzymatic pre-treatment considerably increases yield (14%-22%) and clarification (90%). After enzymatic treatment, the best liquefaction was observed in orange juice, whereas the best clarification was obtained in apricot juice. Additionally, the pectinolytic treatment of apricot juice resulted in the highest increase in reducing sugar concentration (11%) compared to all other enzymatically treated juices. Optimizing the production of a highly active pectinolytic complex and its efficient utilization in the processing of fruit juices, including the generation of an increasing amount of waste, are the significant outcomes of this research.

Optimization of Esterase Production in Solid-State Fermentation of Agricultural Digestate

The continuous increase in biogas production poses the need for innovative applications for its by-products. Solid-state fermentation (SSF) has regained attention in the development of several products because of the possibility to use low-cost and easily available substrates, such as organic wastes. SSF represents a valuable process for agricultural digestate valorization in terms of enzyme production. In the present study, cellulase and esterase were produced by Trichoderma asperellum R on a digestate-based substrate in SSF, with esterase as the highest obtained activity. After assessing the effect of light on it, the esterase production in SSF was optimized using response surface methodology. The influence of substrate composition, temperature and humidity on the enzyme production was evaluated on two sets of data generated based on digestate concentration (50% and 70% w/w). The statistical analyses revealed that these parameters affected esterase production only when Trichoderma asperellum grew on substrate containing 50% w/w of digestate. The best esterase activity (264.6 mU/mg total protein) was achieved with the following optimized SSF parameters: 50% digestate, 50% fruits, 10% sawdust, 30 °C. The current finding of esterase production on digestate-based substrates makes the SSF method presented here a sustainable and completely circular technology.

Pilot-scale process to produce bio-pigment from Monascus purpureus using broken rice as substrate for solid-state fermentation

Pilot-scale process to produce bio-pigment from Monascus purpureus using broken rice as substrate for solid-state fermentation

Pectinase Production from Saccharomyces Cerevisiae Using Orange Peels and Maize Cobs as Substrate for Solid-State Fermentation

Background of the Study: Degradation of wastes especially fruit waste is important because these wastes accumulate in the environment. The fruit wastes can be used to biosynthesize pectinase enzyme at a cheaper rate due its numerous industrial applications. The ability of Saccharomyces cerevisiae to degrade these wastes to produce pectinase enzyme was exploited.&#x0D; Aim: The aim of this study is to isolate and characterize Saccharomyces cerevisiae and study the optimal conditions needed for pectinase production on the orange peel with maize cobs and study the effectiveness of the enzymes produced in the extraction of orange juice.&#x0D; Place and Duration of Study: The study was conducted at the Microbiology Laboratory of Abubakar Tafawa Balewa University Bauchi, Bauchi State, Nigeria, between August to September 2021.&#x0D; Methodology: Soil samples from the orange seller stand was collected, serial dilution method was used to reduce the solution to a more usable concentration, and the samples were streaked on Yeast Peptone Dextrose Agar (YPDA). The plates were incubated for 3 to 9 days at 28+- oC. The isolated yeast was identified based on the morphological and biochemical test, the isolates were inoculated on the prepared fermentation media under different optimal conditions. The crude enzyme were extracted, and the extracts were tested for pectinase activity using the dinitrosalicylic reagent (DNS) method for the presence of reducing sugar. The resulting pectinase was determined to effectively extract juice from orange mash.&#x0D; Results: Saccharomyces cerevisiae showed relatively pectinase hydrolysis using orange peels and maize cobs as substrate by solid-state fermentation under predetermined optimum fermentation conditions. Optimization for the pectinase production was done by altering the conditions for the production medium. Pectinase activity of (2.81 + 2.31 ug/ml) was observed at 72hr of incubation at 35oC.&#x0D; Conclusion: The study demonstrates that orange peel and maize cob can be successfully used to induce the production of pectinase using Saccharomyces cerevisiae under solid-state fermentation.

Improvement of β-galactosidase production by solid-state fermentation using cauliflower (Brassica oleraceae var. botrytis) waste by Enterobacter aerogenes KCTC2190

In this present study, cauliflower wastes were employed as a substrate for better β-galactosidase production by Enterobacter aerogenes KCTC2190. Cauliflower leaf and stalk were used separately as substrates for solid state fermentation. 10% cauliflower stalk enhanced β-galactosidase production at the maximum level. Cultural parameters such as incubation period, temperature and pH were optimized. Maximum β-galactosidase was produced at 40ºC at pH 7 containing cauliflower stalk supplemented medium after 30 h of incubation.

Carposome productivity of Pleurotus ostreatus and Pleurotus eryngii growing on agro-industrial residues enriched with nitrogen, calcium salts and oils

The suitability of the abundant agro-industrial residues wheat straw (WS; control), barley and oats straw (BOS) and rice husk (RH), supplemented with various sources of oils (sunflower, corn oil), nitrogen (peptone, yeast extract) and calcium salts (CaSO4·2H2O, CaCl2), as novel substrates in solid-state fermentation of selected Pleurotus ostreatus and P. eryngii mushrooms was investigated. The possible effect of different additives on mycelial growth rate, biomass production and endoglucanase, laccase and lipase biosynthesis were evaluated. Moreover, their impact on essential cultivation aspects (earliness, total mushroom yield, biological efficiency) and carposome quality parameters (weight, morphological characteristics) was assessed. Both fungi showed their highest growth rates on BOS substrates and the most positive implementation was CaSO4·2H2O 6 % w/w (Kr = 9.58 mm/ day; P. ostreatus, Kr = 9.42 mm/ day; P. eryngii), while different additives led to enhancement of biomass production. Pleurotus species demonstrated minimal levels of endoglucanase activity, with values ranging from 0.01 to 0.42 U/g of dry weight, regardless of the substrate and the stage of colonization. On the contrary, the maximum values of laccase activity were observed at 50 % of colonization on BOS and RH, while supplementation with nitrogen and calcium sources positively affected its biosynthesis. P. ostreatus and P. eryngii cultivated on BOS supplemented with peptone at 2 and 5 % w/w, synthesized significant laccase amounts, i.e., 12,165.78 and 8,624.55 U/g d.w., respectively. Satisfactory amounts of lipase were produced, especially in substrates supplemented with sunflower 2 % w/w, in quantities up to 1.42 U/g d.w., whereas the highest lipase activity was achieved by P. eryngii on WS supplemented with corn oil at 2 % w/w, with a value of 4.25 U/g d.w. being recorded. Regarding fermentation of Pleurotus species in polypropylene bags, WS and BOS supported faster colonization and shorter earliness period than RH substrates, whereas supplementation did not seem to affect these culture parameters. Furthermore, oils supplementation had a positive effect on BE of both species, with values up to 100 % for P. ostreatus and 80 % for P. eryngii on WS and BOS, whereas on RH the lowest BE values were detected. Morphological characteristics were not significantly affected by the additives. Results indicate the positive impact that certain additives have on mushroom productivity and production of enzymes with great financial and environmental importance.

Potential of Red, Green and Brown Seaweeds as Substrates for Solid State Fermentation to Increase Their Nutritional Value and to Produce Enzymes.

Seaweeds are valuable feedstocks with the potential to be used as ingredients in aquafeeds. However, their use are still limited, given their recalcitrant polysaccharide structure. To break this structure, a biotechnological approach such as solid-state fermentation (SSF) by filamentous fungi can be used, which simultaneously increases the nutritional value of the biomass. However, SSF has hardly been studied in seaweeds; thus, in this study, five different seaweeds (Gracilaria sp., Porphyra dioica, Codium tomentosum, Ulva rigida, and Alaria esculenta) were used as substrates in SSF with Aspergillus ibericus MUM 03.49 and A. niger CECT 2915. Firstly, the seaweeds were fully characterized, and, then, changes in the crude protein and carbohydrate contents were assessed in the fermented biomass, as well as any carbohydrases production. The SSF of U. rigida with both fungi resulted in the maximum xylanase and β-glucosidase activities. The maximum cellulase activity was achieved using Gracilaria sp. and U. rigida in the SSF with A. niger. The protein content increased in C. tomentosum after SSF with A. ibericus and in U. rigida after SSF with both fungi. Moreover, U. rigida's carbohydrate content decreased by 54% and 62% after SSF with A. ibericus and A. niger, respectively. Seaweed bioprocessing using SSF is a sustainable and cost-effective strategy that simultaneously produces high-value enzymes and nutritionally enhanced seaweeds to be included in aquafeeds.

Bacillus thuringiensis Production Through Solid-State Fermentation Using Organic Fraction of Municipal Solid Waste (OFMSW) Enzymatic Hydrolysate

This paper aims to explore an alternative pathway to valorize the organic fraction of municipal solid waste. It is based on the use of enzymatic hydrolysis to obtain a sugar-rich fraction with the potential for liquid fermentative processes and a partially hydrolyzed solid that is evaluated as a substrate for solid-state fermentation. Different strategies to modify the pH of the solid substrate to reach a neutral pH, suitable for the growth of biopesticide producer Bacillus thuringiensis, have been explored. The use of alkaline cosubstrates was evaluated on two different scales and temperature was assessed as a preliminary indicator of the scale-up viability of the process strategy. By ensuring a proper pH throughout the process, the growth and sporulation of Bacillus thuringiensis were achieved. The best cosubstrates and mixing ratios were 50% of digested sewage sludge and 25% of digested organic fraction of municipal solid waste, which led to a spore concentration of 1.1 × 109 spores g−1 of dry matter and 6.4 × 108 spores g−1 of dry matter, respectively. Overall, a reproducible and flexible solid-state fermentation process has been achieved for hydrolyzed organic municipal waste based on the use of alkaline urban wastes as cosubstrates. This valorization pathway fits with the concept of urban biorefineries.Graphical