Solid-state Fermentation Process Research Articles

​Comparative Evaluation of Dietary Raw and Solid-state Fermented Sesbania Leaf Meal in Labeo rohita (Hamilton, 1822)

Background: Sesbania aculeata leaf are rich in nutrients which makes it a potential ingredient in fish feed preparation. Solid-state fermentation (SSF) process of leaf enhanced nutrient content and reduced antinutritional factors. This experiment was conducted to optimize inclusion of raw and fermented S. aculeata leaf meal (RSLM and FSLM) in the diet of Labeo rohita at fingerling stage at different level. Methods: Nine isonitrogenous (30% CP) diet for rohu fingerlings were prepared using RSLM and FSLM. SSF of the leaf meals were carried out using Bacillus subtilis. Feeding trail was conducted for 60 days at RSLM inclusion level of 10, 20, 30 and 40% (T1, T2, T3, T4) and FSLM (T5, T6, T7, T8) in triplicate treatments with 0% inclusion as control (C). Result: The fish fed with FSLM based diet had higher weight gain (%), SGR (%) and lower FCR when compared to RSLM and Control. S. aculeata can be incorporated in rohu fingerling’s diet upto 20% RSLM and 40% FSLM level without any adverse effect on the growth of the fish.

Phenolic compounds and antioxidant activity of Lippia graveolens Kunth residual leaves fermented by two filamentous fungal strains in solid-state process

The residual leaves from essential oil extraction from Mexican oregano (Lippia graveolens) have a potential as a source of bioactive molecules (e.x. flavonoids) that could be extracted by solid state fermentation (SSF) process. In this study, the residual leaves were subjected to a SSF (120 h) by two microorganism Trichoderma harzianum and Rhizopus oryzae evaluating the phenolic compounds (Total polyphenols and flavonoids), the antioxidant activity (DPPH● / FRAP), the bioactivities (α-amylase inhibition and antimicrobial against Escherichia coli), the cytotoxic effect (erythrocytes) and a characterization (HPLC-MS). The results showed that the total polyphenols for T.harzarium did not show statistical differences (first 48 h), and R. oryzae fermentation obtained a higher context (48 h). Also, the higher flavonoid release was present at 48 and 96 h (T. harzianum and R. oryzae). The antioxidant activity decreased in the last fermentation hours, the a-amylase reported a higher inhibition value (29.97 ± 1.97 %) and antimicrobial capacities; R. oryzae (96 h) did not register a cytotoxic effect. The characterization determined the presence of valuable molecules as ferulic acid 4-O-glucoside, phloridzin and luteolin. The fermentation allowed the recovery of bioactive phenolic compounds that could be an alternative for the revalorization of oregano waste.

EXTRACTION AND ACTIVITIES OF CRUDE PROTEASES FROM SOLID STATE FERMENTATION OF Aspergillus nigeR GROWN ON VARIOUS AGRO WASTE

Agro-industrial residues are generally considered the best substrates for the solid-state fermentation process. Food processing wastes such as shells of nuts and eggs in Nigeria are usually disposed in dumpsites or are incinerated, causing environmental pollution. This study extracted, estimated and compared enzyme activities from Aspergillus niger under solid-state fermentation (SSF) by utilizing Ground nut shell (GS), Bambara nut shell(BS), Guinea fowl egg shell(GFS) and Layer egg shells (LES) powder as solid substrates. The Agro wastes were dried under the sunlight for four days, ground using a laboratory pestle and mortar separately and sieved to obtain fine powder. The powder was sterilized, supplemented with sodium acetate buffer and pure casein, inoculated with the fungi then left to ferment for six days. The crude extract of the substrates were obtained by filtration and centrifugation. The extracts were assayed for enzyme activity using Sigma Aldrich’s method of assay. The result obtained from the assay demonstrated that proteases were active in all the extracts. However, there was significantdifference (P < 0.05) in protease activities in the samples studied. The result revealed that BS and LES showed the highest enzymatic activities (0.797± 0.035 μ/ml), (0.788 ± 0.028 μ/ml), (0.574 ± 0.032 μ/ml), (0.590± 0.040 μ/ml) at 0.2, 0.4, 0.6 and 0.8ml of the crude enzyme extract volume concentrations respectively followed by GS which had the enzymatic activities (0 .456 ±0.001 μ/ml), (0.391 ± 0.003 μ/ml), (0.335 ± 0.003 μ/ml), (0.205± 0.032 μ/ml) at the volume extract volume concentrations of 0.2, 0.4, 0.6, 0.8ml respectively, meanwhile guinea fowl egg shell had the least enzymatic activities (0.401± 0.028 μ/ml), (0 .336 ± 0.047 μ/ml), (0.250 ± 0.018 μ/ml), (0.255 ± 0.010 μ/ml) at the volume of crude enzyme extract of 0.2, 0.4, 0.6, 0.8ml respectively. In all the shells the highest proteases activities were recorded at 0.2ml of the crude extract volume concentration and the least proteases activities were recorded at 0.8ml of then crude extract volume concentration. This study has proven that proteases were extracted and active from solid state fermentation of Aspergillus niger grown on various agro waste, Therefore proper utilization of these agro-wastes in industrial and scientific settings will not only serve as means of polluted environmental remediation but also as an iualternative to commercially available substrates for microbial growth.

Effect of solid-state fermentation and ultrasonication processes on antimicrobial and antioxidant properties of algae extracts.

Algal biomass (AB) is prospective source of valuable compounds, however, Baltic Sea macroalgae have some challenges, because of their high microbial and chemical contamination. These problems can be solved, by using appropriate technologies for AG pre-treatment. The aim of this study was to evaluate the influence of two pre-treatments, solid-state fermentation with the Lactiplantibacillus plantarum LUHS135 and ultrasonication, on the antioxidant and antimicrobial characteristics of macro- (Cladophora rupestris, Cladophora glomerata, Furcellaria lumbricalis, Ulva intestinalis) and Spirulina (Arthrospira platensis) extracts. Also, combinations of extracts and LUHS135 were developed and their characteristics were evaluated. The total phenolic compound content was determined from the calibration curve and expressed in mg of gallic acid equivalents; antioxidant activity was measured by a Trolox equivalent antioxidant capacity assay using the DPPH• (1,1-diphenyl-2-picrylhydrazyl), ABTS•+ 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), FRAP (Ferric Reducing Ability of Plasma) discoloration methods. Antimicrobial activity was measured by using agar well diffusion assay and in a liquid medium. The highest DPPH• and ABTS•+ was shown by C.rupestris and F.lumbricalis extract × LUHS135 combinations, the highest FRAP - by non-pretreated C.rupestris and F.lumbricalis extract × LUHS135 combinations. Ultrasonicated samples inhibited four out of seven tested pathogens. Finally, the tested pre-treatments showed good perspectives and can be recommended for AB valorization.

Co-production of biogas and humic acid using rice straw and pig manure as substrates through solid-state anaerobic fermentation and subsequent aerobic composting

Compared with wet anaerobic digestion, solid-state fermentation possesses many merits such as low water consumption, high biogas yield and low processing cost. In this work, co-producing biogas and humic acid (HA) by two-step solid-state fermentation was innovatively investigated using rice straw and pig manure as materials. The result indicates that C/N ratio, straw particle size, and total solid content (TS%) caused significant effects on the solid-state fermentation process. At the first step for anaerobic biogas fermentation, the optimal fermentation conditions included C/N ratio of 27.5, straw particle size of 0.85 mm and TS% of 25%. The maximal biogas productivity and methane content were up to 0.43 m3/(m3·d) and 64.88%, respectively. This means that biogas production was significantly improved by adjusting C/N ratio during the co-fermentation of rice straw and pig manure. Following, the digested residue was aerobically composted for HA biosynthesis to improve the fertilizer efficiency of the fermented substrate. The optimal aeration rate of 0.75 L/min was obtained, and the volatile solid (VS) degradation rate, HA content, and the germination index (GI) value were up to 19.16%, 100.89 mg/g, and 103.07%, respectively, which indicates that HA biosynthesis and compost maturity were significantly enhanced. Therefore, the co-production of biogas and HA using rice straw and pig manure as fermentation materials was achieved by adopting the two-step solid-state fermentation, and the bioconversion efficiencies of livestock manure and straw were significantly improved.

Antifungal Agent Chitooligosaccharides Derived from Solid-State Fermentation of Shrimp Shell Waste by Pseudonocardia antitumoralis 18D36-A1

Shrimp shell waste is a potential source of the biopolymer chitin. Through fermentation, chitin can be converted into its derivative products. This study aimed to isolate and characterize the products of the biodegradation of chitin from shrimp shell waste through a solid-state fermentation process using actinomycetes. Actinomycete isolates were obtained from tunicate marine biota collected from the waters of Buleleng, Bali, using a dilution technique on 1% chitin colloid agar medium. The isolated actinomycetes were cultivated on a shrimp shell waste medium for 7 days, and then the products of the biodegradation of the oligomers were extracted using water. The extracts of the biodegradation products of the shrimp shells were isolated through several chromatographic steps and analyzed using LC–MS–MS, and the bioactivity of the biodegradation products against fungi was tested. The morphological observations and phylogenetic analysis showed that the isolate 18D36-A1 was a rare actinomycete with the proposed name Pseudonocardia antitumoralis 18D36-A1. The results of the analysis using TLC showed that the solid-state fermented water isolate 18D36-A1 produced several oligomeric components. These results indicate that the isolate 18D36-A1 was able to convert chitin into chitooligosaccharides. Further isolation of the extract produced the active fraction D36A1C38, which can inhibit the growth of fungi by 74% at a concentration of 1 mg/mL. This initial information is very important for further studies related to the development of a solid-state fermentation process for obtaining bioactive compounds from shrimp shell waste.

"Designing, Developing and Optimizing a Two-Stage Solid State Fermentation Process through valorization of Cereal Milling and Legume By-Products and Waste Streams for the Production of Novel Functional Protein Rich Type-Miso Nutri-Powder, Using Aspergillus Oryzae"

Antonios E Koutelidakis, Christina Dimou, Nidopoulou Konstantina and Charalampia M Dimou* Author Affiliations Department of Food Science and Nutrition, Unit of Nutrition, University of the Aegean, School of the Environment, Greece Received: June 14, 2022 | Published: June 22, 2022 Corresponding author: Charalampia M Dimou, Human Nutrition Unit, Laboratory of Nutrition and Public Health, Food Science and Nutrition Department, University of the Aegean, 11472 Myrina, Greece DOI: 10.26717/BJSTR.2022.44.007093

Transformation of mixtures of olive mill stone waste and oat bran or Lathyrus clymenum pericarps into high added value products using solid state fermentation

The main objective of this study concerns the bioconversion of agro-industrial wastes into high added value products, such as proteinaceous animal feed, using Solid State Fermentation process (SSF). For this purpose, the Olive Mill Stone Waste (OMSW) which is known to contain low amounts of proteins and a high concentration of anti-nutritional substances was used as substrate. Subsequently, OMSW was fermented with Oat Bran (OB) or Lathyrus clymenum pericarp (LP) in proportions varying from 10 %w/w to 30 %w/w, applying SSF process initiated by Pleurotus ostreatus utilizing latter’s secreted enzymes for their degradation. The respective results indicated that the addition of 30 %w/w of OB, resulted in a 39% increase of the protein content at the end of fermentation (Day 21). In addition, we observed a 5-fold increase of 1,3–1,6 β-glucan content and a simultaneous decrease of unwanted lignin of 24%. The addition of 20 %w/w of LP afforded, at the end of fermentation (Day 21), an increased protein content of 57%, a 3-fold increase in 1,3–1,6 β-glucans and a decrease in lignin concentration of 13%. These findings demonstrate the potential of the LP utilization by using SSF process, for the production of high nutritional value dietary supplements for animal feed. This endeavor constitutes the first literature report for the utilization of the agro-industrial waste LP. The developed methodology herein is considered as crucial for the circular economy since it refers to the reuse of agro-industrial wastes and the production of a high added-value product.

Chinese Baijiu: The Perfect Works of Microorganisms.

Chinese Baijiu is one of the famous distilled liquor series with unique flavors in the world. Under the open environment, Chinese Baijiu was produced by two solid-state fermentation processes: jiuqu making and baijiu making. Chinese Baijiu can be divided into different types according to the production area, production process, starter type, and product flavor. Chinese Baijiu contains rich flavor components, such as esters and organic acids. The formation of these flavor substances is inseparable from the metabolism and interaction of different microorganisms, and thus, microorganisms play a leading role in the fermentation process of Chinese Baijiu. Bacteria, yeasts, and molds are the microorganisms involved in the brewing process of Chinese Baijiu, and they originate from various sources, such as the production environment, production workers, and jiuqu. This article reviews the typical flavor substances of different types of Chinese Baijiu, the types of microorganisms involved in the brewing process, and their functions. Methods that use microbial technology to enhance the flavor of baijiu, and for detecting flavor substances in baijiu were also introduced. This review systematically summarizes the role and application of Chinese Baijiu flavor components and microorganisms in baijiu brewing and provides data support for understanding Chinese Baijiu and further improving its quality.

A Simplified Techno-Economic Analysis for Sophorolipid Production in a Solid-State Fermentation Process

Sophorolipids (SLs) are microbial biosurfactants with an important role in industry and a continuously growing market. This research addresses the use of sustainable resources as feedstock for bioproducts. Winterization oil cake (WOC) and molasses are suitable substrates for SLs via solid-state fermentation (SSF). The model proposed herein was established for annually processing 750 t of WOC and comparing three support materials: wheat straw (WS), rice husk (RH), and coconut fiber (CF). Production capacity ranged 325–414 t of SLs per year. Unit Production Cost was 5.1, 5.7, and 6.9 USD/kg SL for WS, RH, and CF production models, respectively, and was slightly lower with other substrates. Financial parameters were CAPEX 6.7 MM USD and OPEX 1.9 MM USD/y, with a NPV, IRR and payback time of 6.4 MM USD, 31% and 3.2 y, respectively. SLs recovery from the solid matrix was the major contributor to operating costs, while fermentation equipment shaped capital costs. Results show that the physical properties (bulk density, WHC) of substrates and supports define process costs beyond substrate purchase costs and process yields in SSF systems. To our knowledge, this is the first attempt to model SLs production via SSF at full scale for the economic valuation of the SSF process.

Arabinoxylans Release from Brewers' Spent Grain Using Extrusion and Solid-State Fermentation with Fusarium oxysporum and the Antioxidant Capacity of the Extracts.

Brewers’ spent grain (BSG) is the most abundant byproduct generated from the beer-brewing process. BSG is a material rich in hemicellulose, composed of arabinoxylans (AX). However, the high crosslinking of this material causes low availability of AX, for which it is necessary to apply different treatments. The objective of this research is to increase the release of arabinoxylans through solid-state fermentation with Fusarium oxysporum f. sp. lycopersici using extruded brewery spent grain. First, the BSG is subjected to two types of physical treatments: extrusion at 20% moisture, 200 rpm and 50 °C (BSGe), and blade milling (BSGm). The chemical composition is determined for each sample (BSG, BSGe and BSGm). Subsequently, the solid-state fermentation process (SSF) is carried out on each sample. The fermentation kinetics at 30 °C are monitored for 7 days. Once the SSF concludes, AX are extracted, and the purity of AX is determined by the phloroglucinol colorimetric assay. Finally, the total phenolic compounds, phenolic acids and antioxidant capacity by DPPH are quantified. No significant differences (p ≥ 0.05) in the protein, lipid, ash or total dietary fiber contents are found among the samples. No significant difference (p ≥ 0.05) in the content of soluble fiber is found, although BSGe and BSGm have higher values than BSG. On the other hand, the yields of soluble AX exhibit significant differences (p ≤ 0.05) among nonfermented samples (BSG, 0.03%; BSGm, 0.53%; BSGe, 0.70%) and with SSF (BSG, 2.95%; BSGm, 6.24%; and BSGe, 9.58%). In addition, the contents of free phenolic compounds and free phenolic acids and the percent inhibition of free extracts by 2,2-diphenyl-1-picrylhydrazyl (DPPH) differ significantly (p ≤ 0.05) between samples subjected to SSF and nonfermented samples. Therefore, extrusion and SSF treatment increase AX release from BSG as well as the antioxidant capacity of the extracts.

Evaluation of ultrasound waves for the production of chitinase and β-1,3 glucanase by Trichoderma harzianum through SSF.

Cell wall degrading enzymes (chitinase and β-1,3-glucanase) were produced by solid-state fermentation (SSF) using the fungus Trichoderma harzianum and different agro-industrial products, mainly residues. The influence of temperature (25-35°C), initial moisture content (50-90% w/w), nutrient solution (1-2% v/w), and yeast extract (1-2% w/w) on enzyme activity was evaluated. The application of ultrasound during fermentation for different times (0-6h/day) was also studied. White rice was the substrate that showed the highest chitinase and β-1,3-glucanase activities, which were 31.31 U/g for chitinase and 23.83 U/g for β-1,3-glucanase after 10days of fermentation. Application of ultrasound waves during fermentation positively affected (p < 0.05) the enzyme activities. The best results for chitinase (51.88 U/g) and β-1,3-glucanase (39.22 U/g) were obtained with a 50% (w/w) moisture content and 4h/day ultrasound application for 10days of fermentation. Increases of 3.6-fold (from 14.37 to 51.88 U/g) and 3.8-fold (from 10.22 to 39.22 U/g) in activities for chitinase and β-1,3-glucanase, respectively, compared to non-sonicated fermentation, were obtained. Ultrasound technique associated with the SSF process was a promising alternative to increase the production activity of cell wall degrading enzymes: chitinase and β-1,3-glucanase.

Potentialities of Fermented Cashew Apple Bagasse with Penicillium roqueforti ATCC 10110: Total Phenolics, Antifungal Activity and Cytotoxicity

In this study, cashew apple (Anacardium occidentale L.) bagasse, a residue from the industrial extraction of the juice, was subjected to a solid-state fermentation process with the fungus Penicillium roqueforti ATCC 10110 and the total phenolic content was evaluated, as well as the activity of extracts against strains of dermatophyte fungi of the genera Trichophyton and Microporum; cytotoxicity was analyzed through hemolytic potential in human erythrocytes. The results showed that the fermented cashew apple bagasse had a higher content of total phenolics compared to the unfermented bagasse, a potent antifungal activity with minimum inhibitory concentrations (MIC) ranging from 256 to 512 μg/mL against the strains: T. rubrum (LM-115 and LM-629), T. mentagrophytes LM-119, M. gypseum LM-512 and M. canis (LM-68 e LM-110), with low cytotoxicity. Therefore, the fermented extracts of cashew apple bagasse can be considered as a promising natural non-toxic product for studies in the development of agents against skin diseases, especially for the treatment of dermatophytosis.

Comparison of Liquid and Solid-State Fermentation Processes for the Production of Enzymes and Beta-Glucan from Hulled Barley.

Solid-state fermentation using hulled barley was carried out to produce enzymes and β-glucan. The one-factor-at-a-time experiments were carried out to determine the optimal composition of the basal medium. The modified synthetic medium composition in liquid-state fermentation was determined to be 70 g/l hulled barley, 0 g/l rice bran, 5 g/l soytone, and 6 g/l ascorbic acid. Optimal pretreatment conditions of hulled barley by solid-state fermentation were evaluated in terms of maximum production of fungal biomass, amylase, protease, and β-glucan, which were 1.26 mg/g, 31310.34 U/g, 2614.95 U/g, and 14.6% (w/w), respectively, at 60 min of pretreatment condition. Thus, the solid-state fermentation process was found to enhance the overall fermentation yields of hulled barley to produce high amounts of enzymes and β-glucan.

The Impact of Fermentation on Bee Pollen Polyphenolic Compounds Composition.

Bee-collected pollen is one of the most valuable natural products. However, the pollen cell walls limit the digestibility and release of nutrients to the human body. Solid-state lactic acid fermentation can be used to ease the release of bioactive compounds from the pollen cell. The aim of this research was to determine the impact of a solid-state lactic acid fermentation process on biologically active compound composition and antioxidant activity of bee-collected pollen from various European regions (Italy, Netherlands, Lithuania, Poland, Sweden, Denmark, Malta, Slovakia, and Spain). Spontaneous fermentation and fermentation using an L. rhamnosus culture were performed. The total content of phenolic compounds, total content of flavonoids, and radical (DPPH) scavenging activity were measured by spectrophotometric tests, while UPLC was employed for quantification of phenolic compounds. The determined fermentation positive effects included an increase of total phenolic content by 1.4–2.3 times, total flavonoid content by 1.1–1.6 times, and radical scavenging activity by 1.4–2.3 times. Naringenin (21.09–135.03 µg/g), quercetin (6.62–78.86 µg/g), luteolin (29.41–88.90 µg/g), and rutin (21.40–89.93 µg/g) were the most abundant flavonoids in all samples; however, their variation level was both geographical in origin and fermentation-type dependent. Fermentation increased the content of phenolic acids with high antioxidant potentials such as ellagic, ferulic and caffeic, while reduction of chlorogenic acid was determined.

Soybean extruded by‐products as substrate for obtaining food ingredients containing probiotics

SummaryExtruded expeller meal (EEM) was widely used for feed production, but few exploited it as a food ingredient. Solid‐state fermentation (SSF) was applied for obtaining food ingredients (FI) based on EEM containing Lacticaseibacillus casei. The FI were characterised physicochemically and functionally. The effect of the SSF on these characteristics as well as the effect of the expeller matrix on the survival capacity of L. casei in in vitro gastrointestinal digestion and on epithelial adhesion were analysed. In general, the SSF process did not produce significant changes on the nutritional and functional properties studied. Probiotic cells supported in the FI were stable for 42 days showing &gt;106 log (CFU g−1) viable probiotic microorganisms. More than 60% of them survived to gastrointestinal simulated conditions. Expeller matrix interfered the adhesion of L. casei with the epithelium. The FI could be incorporated to a porridge for improving the nutritional profile and providing functionality.

A systematic study of the production of Monacolin K by solid state fermentation of Monascus ruber

Monacolin K is one of the bioactive substances produced by Monascus ruber during fermentation. The multi-factors and their interactions on the effect of solid-state fermentation of Monascus for high yield of monacolin K were attractive to industrial production. A detailed study of 7 single-factor experiments and a series of experiments with Plackette-Burman and Box-Benhnken design, data fitting and modeling, and analyzing the visual 3D response surface plots for investigation of the key factors for Monacolin K production. The results showed that initial moisture (50 ~ 55%) and bran content (4.5 ~ 5.5%) as the key factors of transport for nutrients and oxygen during the solid-state fermentation (SSF) process of Monascus. Under the optimal conditions, a temperature shifting of the SSF with a higher Monacolin K yield of 14.53 ± 0.16 mg·g− 1 compared with the content of monacolin K in the commercially available functional red yeast rice of 8 mg g− 1.

Identification of New Natural Sources of Flavour and Aroma Metabolites from Solid-State Fermentation of Agro-Industrial By-Products.

Increasing consumer demand for natural flavours and fragrances has driven up prices and increased pressure on natural resources. A shift in consumer preference towards more sustainable and economical sources of these natural additives and away from synthetic production has encouraged research into alternative supplies of these valuable compounds. Solid-state fermentation processes support the natural production of secondary metabolites, which represents most flavour and aroma compounds, while agro-industrial by-products are a low-value waste stream with a high potential for adding value. Accordingly, four filamentous fungi species with a history of use in the production of fermented foods and food additives were tested to ferment nine different agro-industrial by-products. Hundreds of volatile compounds were produced and identified using headspace (HS) solid-phase microextraction (SPME) coupled to gas chromatography–mass spectrometry (GC–MS). Four compounds of interest, phenylacetaldehyde, methyl benzoate, 1-octen-3-ol, and phenylethyl alcohol, were extracted and quantified. Preliminary yields were encouraging compared to traditional sources. This, combined with the low-cost substrates and the high-value natural flavours and aromas produced, presents a compelling case for further optimisation of the process.

High production of jasmonic acid by Lasiodiplodia iranensis using solid-state fermentation: Optimization and understanding.

Jasmonic acid (JA) is a plant hormone involved in regulating developmental and growth controls as well as photosynthesis. In addition, this hormone protects the plant against insects and has good applications in agriculture, the flavored industry and other fields. Filamentous fungus generally produces JA using liquid static culture. In the present study, a solid-state fermentation (SSF) method is developed for high production of JA using Lasiodiplodia iranensis. By selecting the solid substrate and optimizing the initial water content, inoculum volume, loading volume and other culture conditions, the maximum JA yield reached 5306.38mg kg-1 when fermented for 12 days in a petri dish containing a medium with crushed wheat as the solid substrate and 75% initial water content. The logistic and Luedeking-Piret models were used to characterize the relationship between microbial growth and product synthesis in the SSF process, and the maximum JA production is predicted to be 5263.23mg kg-1 , which is close to the experimental value. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) is used to examine the metabolic changes that develop during fermentation. The results indicate that JA biosynthesis occurs in the α-linolenic acid metabolic pathway, of which 13(S)-HpOTrE is a key intermediate metabolite and both 13(S)-HOTrE and traumatic acid are byproducts of the branches of its synthesis. The results of this study provide a method for obtaining high JA yields by SSF, and offer new insights for understanding the production of JA by fungal fermentation.

Breeding of New Saccharomyces cerevisiae Hybrids with Reduced Higher Alcohol Production for Light-Aroma-Type-Xiaoqu Baijiu Production

Baijiu, also referred to as "Chinese liquor", is a traditional spirit that originated in China over 2000 years ago and is the world’s bestselling liquor today. It is produced using a solid-state fermentation process, often using sorghum as raw material, in which a complex microbial cocktail (called "Jiuqu") is introduced to initiate the fermentation process. During fermentation, a plethora of flavor-active metabolites is produced by microbes. Depending on the flavors formed, Baijiu can be subdivided into sauce-aroma-type, strong-aroma-type, and light-aroma-type. A key feature of light-aroma-type Xiaoqu Baijiu (LATXB) is its relatively low concentration of higher alcohols (HA). However, reaching sufficiently low HA concentrations without affecting the overall taste and flavor of LATXB is often difficult. In this project, breeding was used to develop a new Saccharomyces cerevisiae hybrid strain for LATXB production, which shows reduced HA production. This strain, dubbed “hybrid 5”, reduced total HA by 10.3%, without compromising the production of other metabolites or fermentation efficiency when evaluated at an industrial scale (2 tons). Together, these results show the potential of breeding to produce superior, non-GM yeasts that are directly applicable for commercial Baijiu production.