Fermentation

Research

14 pages, 1174 KiB

Open AccessArticle

Assessment of Alternative Media Viability for Cell Growth Phase in the Lab-Scale Xanthan Pruni Production—Part I

by Isabel Santos Pedone, Fabíola Insaurriaga Aquino, Eduardo dos Santos Macedo Costa, Karine Laste Macagnan, Jéssica da Rosa Porto, Anderson Schwingel Ribeiro, Mariane Igansi Alves, Claire Tondo Vendruscolo and Angelita da Silveira Moreira

Fermentation 2025, 11(4), 191; https://doi.org/10.3390/fermentation11040191 - 3 Apr 2025

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Abstract

Xanthan is a highly relevant commercial microbial biopolymer. Its production occurs in two steps: the bacterium is cultivated in a nitrogen-rich medium for cell multiplication, and the obtained biomass is used as an inoculum for the polymer production phase. Different media compositions for [...] Read more.

Xanthan is a highly relevant commercial microbial biopolymer. Its production occurs in two steps: the bacterium is cultivated in a nitrogen-rich medium for cell multiplication, and the obtained biomass is used as an inoculum for the polymer production phase. Different media compositions for cell growth were investigated, seeking to reduce or replace the peptone used in the standard medium. Peptone (P), yeast extract (YE), and rice parboiling water (RPW) concentration combinations were tested in cultivating Xanthomonas arboricola pv. pruni 101. A CRD 2³ design, performed in a shaker, was used to assess the effects of independent variables on xanthan pruni microbial growth, N consumption, yield, viscosity, pseudoplasticity, and xanthan mineral content. After 24 h an increase in N was observed, without any significant impact on cell growth. Xanthan yield increased as a result of the alternative treatments, with P and YE influencing positively. However, T1, with the lowest levels of P, YE, and RPW increased viscosity and pseudoplasticity of xanthan pruni. RPW increased phosphorus, silicon, calcium, and magnesium, and P and YE increased potassium. These results indicate that partial replacement of P by RPW and YE is an economically viable and sustainable approach for the xanthan pruni production. Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control: 2nd Edition)

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15 pages, 457 KiB

Open AccessArticle

Exopolysaccharide (EPS) Production by Endophytic and Basidiomycete Fungi

by Wai Prathumpai, Umpawa Pinruan, Sujinda Sommai, Somjit Komwijit and Kwanruthai Malairuang

Fermentation 2025, 11(4), 183; https://doi.org/10.3390/fermentation11040183 - 1 Apr 2025

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Abstract

The screening of exopolysaccharides (EPS) produced by 52 isolates of endophytic and basidiomycete fungi was studied on two different media, PDB and PYGM. There were five isolates that could produce dried exopolysaccharide of more than 4 g/L (S. commune LF01962, LF01001, LF01581, [...] Read more.

The screening of exopolysaccharides (EPS) produced by 52 isolates of endophytic and basidiomycete fungi was studied on two different media, PDB and PYGM. There were five isolates that could produce dried exopolysaccharide of more than 4 g/L (S. commune LF01962, LF01001, LF01581, Pycnoporus sp. MMCR00271.1, Pestalotiopsis sp. PP0005). The molecular weights of these exopolymers were found to be in the range of 2.5–500 kDa. These five exopolysaccharides, produced by five different fungal isolates, showed non-cytotoxic activity against NCTC clone 929 and HDFn cell lines. The selected fungal isolate of S. commune LF01962 was used for further optimization of different medium compositions affecting exopolysaccharide production using statistical methods. Among four conditions tested in the first step (xylose + peptone, glucose + (NH₄)₂HPO₄, fructose + peptone, and mannose + yeast extract), mannose + yeast extract resulted in the highest exopolysaccharide production of 5.10 ± 2.00 g/L. In the second step using Plackett–Burman design, the optimal medium for S. commune exopolysaccharide production was found to consist of 40 g/L glucose, 5 g/L mannose, 20 g/L (NH₄)₂HPO₄, 5 g/L yeast extract, 3 g/L monosodium glutamate, 0.5 g/L KH₂PO₄, 0.5 g/L K₂HPO₄, 0.2 g/L MgSO₄, 1 mL/L trace elements, and 3 mL/L vitamin solution, which resulted in 8.16 g/L exopolysaccharide production. Exopolysaccharide production in a 5 L bioreactor using small pellets as seed inoculum was found to produce 18.28 g/L exopolysaccharide. Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control: 2nd Edition)

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11 pages, 226 KiB

Open AccessArticle

Effects of Compound Lactic Acid Bacteria Additives on the Quality of Oat and Common Vetch Silage in the Northwest Sichuan Plateau

by Tianli Ma, Yafen Xin, Xuesong Chen, Xingjin Wen, Fei Wang, Hongyu Liu, Lanxi Zhu, Xiaomei Li, Minghong You and Yanhong Yan

Fermentation 2025, 11(2), 93; https://doi.org/10.3390/fermentation11020093 - 12 Feb 2025

Viewed by 986

Abstract

The objective of this experiment was to determine whether compound microbial inoculants could enhance the fermentation of oat and common vetch silage that were stored in the Northwest Sichuan Plateau for 60 days under extremely low temperatures. Oat and common vetch harvested from [...] Read more.

The objective of this experiment was to determine whether compound microbial inoculants could enhance the fermentation of oat and common vetch silage that were stored in the Northwest Sichuan Plateau for 60 days under extremely low temperatures. Oat and common vetch harvested from single and mixed artificially planted grassland of oat and common vetch were chopped into 2–3 cm (oat, S1; common vetch, S2; oat–common vetch = 2:1, S3), then sterile water (T1), Zhuang Lemei IV silage additive (T2), and Fu Zhengxing silage additive (T3) were added to the feed and ensiled at the local outdoor environment for 60 days. Data were analyzed as a 3 × 3 factorial arrangement of treatments with the main effects of the materials, additives, and their interaction. Interactions between the materials and additives significantly affected the fermentation quality and the content of DM, WSC, and NDF and the number of yeasts in forages. Treatments with S3 have significantly higher contents of lactic acid, acetic acid, and lactic acid bacteria in the feed than those in the S1 and S2 treatments, while the contents of AN/TN and propionic acid were significantly lower compared with the S1 and S2 treatments (p < 0.05). Concentrations of lactic acid, acetic acid, and propionic acid were significantly increased and the content of neutral detergent fiber in the T2-treated silage decreased compared with the T1 treatment (p < 0.05). The T3 treatment significantly reduced the number of yeasts in the silage but the compound lactic acid bacteria additive treatment (T1, T2) significantly decreased the butyric acid content and pH of the feed and increased the acid detergent fiber content and the number of lactic acid bacteria in the feed compared with the T1 treatment. Among them, the butyric acid content of the T3 treatment decreased by 63.64–86.05%, while that of the T2 treatment decreased by 36.36–83.33% (p < 0.05). The comprehensive analysis of the membership function revealed that the silage quality was the best after the S3T2 treatment, so the implementation of the S3T2 combination in the Northwest Sichuan Plateau can provide guarantees for the production of local high-quality forage grass and alleviate the shortage of forage grass. Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control: 2nd Edition)

20 pages, 1807 KiB

Open AccessArticle

The Optimization of the Nutrient Medium Composition for the Submerged Cultivation of the Mycolicibacterium neoaurum Strain VKM Ac-3067D in a 100 L Bioreactor Under Controlled Conditions by Mathematical Planning

by Vera V. Yaderets, Nataliya V. Karpova, Elena V. Glagoleva, Alexandra S. Shibaeva and Vakhtang V. Dzhavakhiya

Fermentation 2025, 11(2), 82; https://doi.org/10.3390/fermentation11020082 - 7 Feb 2025

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Abstract

The biotechnological production of carotenoids offers a promising alternative to their chemical synthesis or extraction from plants. Mycolicibacterium species have shown potential as pigment-producing microorganisms. However, bacterial strains typically exhibit lower productivity compared to fungal and yeast strains. Earlier, we enhanced the β-carotene [...] Read more.

The biotechnological production of carotenoids offers a promising alternative to their chemical synthesis or extraction from plants. Mycolicibacterium species have shown potential as pigment-producing microorganisms. However, bacterial strains typically exhibit lower productivity compared to fungal and yeast strains. Earlier, we enhanced the β-carotene biosynthesis in M. neoaurum strain VKM Ac-3067D by modifying the cultivation medium. Key changes included replacing glucose with glycerol and soybean meal with skimmed milk powder (SMP) and increasing the urea content from 0.5 to 1.0 g/L. To further optimize β-carotene yield, a steepest ascent method was applied combining factorial design with a gradient-based optimization (Wilson–Box method). The resulting regression model showed that the most influential factors were the glycerol concentration and SPM use. The in-flask fermentation of the Ac-3067D strain in a medium containing 25.5 g/L of glycerol (carbon source) and 12.80 g/L of SMP (nitrogen source) increased β-carotene yield to 318.4 ± 8.3 mg/kg. In a 15 L bioreactor, β-carotene yield increased to 432.3 ± 10.4 mg/kg, while the biomass concentration reached 23.2 ± 1.2 g/L. The further scaling up to a 100 L bioreactor increased both β-carotene yield (450.4 ± 8.2 mg/kg) and biomass concentration (25.2 ± 1.1 g/L). Thus, β-carotene production technology using the M. neoaurum strain AC-3067D was successfully scaled up from 750 mL flasks to a 100 L bioreactor, confirming its potential for industrial-scale application. Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control: 2nd Edition)

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16 pages, 2634 KiB

Open AccessEditor’s ChoiceArticle

A New Concept for the Rapid Development of Digital Twin Core Models for Bioprocesses in Various Reactor Designs

by André Moser, Christian Appl, Ralf Pörtner, Frank Baganz and Volker C. Hass

Fermentation 2024, 10(9), 463; https://doi.org/10.3390/fermentation10090463 - 6 Sep 2024

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Abstract

In this research work, a new software tool concept and its application for the rapid and flexible development of mechanistic digital twin core models for bioprocesses in various reactor designs are presented. The newly developed software tool concept automatically combines user-selected submodels into [...] Read more.

In this research work, a new software tool concept and its application for the rapid and flexible development of mechanistic digital twin core models for bioprocesses in various reactor designs are presented. The newly developed software tool concept automatically combines user-selected submodels into an overall digital twin core model. The main part is a biokinetic submodel, of which three were designed for enzymatic, microbial and biocatalytic processes, which can be adapted to specific processes. Furthermore, the digital twin core model contains a physico-chemical submodel (e.g., calculating pH or oxygen transfer) and a reactor submodel. The basis of the reactor submodel is an ideally mixed stirred tank reactor. The biokinetic submodel is decoupled from the reactor submodels and enables an independent parameterisation of submodels. Connecting ideally mixed stirred tank reactor models allows for the simulation of different reactor designs. The implementation of an executable digital twin core model was accelerated, creating a new software tool concept. When the concept was applied, the development time and the computing time of digital twin core models for the cultivation of Saccharomyces cerevisiae in two coupled stirred tank reactors as well as for enzymatic hydrolysis processes in a packed-bed reactor were reduced by 90%. Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control: 2nd Edition)

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12 pages, 3131 KiB

Open AccessArticle

Enhanced Fermentation Process for Production of High Docosahexaenoic Acid Content by Schizochytrium sp. GCD2032

by Liucheng Long, Xiaoqing Ren, Feiyu Zhang, Aijia Shi, Yida Zhai, Wuxi Chen, Yu Duan, Pengbao Shi, Limei Chen and Demao Li

Fermentation 2024, 10(9), 460; https://doi.org/10.3390/fermentation10090460 - 4 Sep 2024

Viewed by 2133

Abstract

There is significant demand for high-purity DHA in the pharmaceutical industry. Traditionally, this high-purity DHA is extracted from raw materials with relatively low DHA content (10–20%), such as fish oil. Recently, through electroporation-induced mutation, a high-DHA-content strain of Schizochytrium sp. GCD2032 was isolated. [...] Read more.

There is significant demand for high-purity DHA in the pharmaceutical industry. Traditionally, this high-purity DHA is extracted from raw materials with relatively low DHA content (10–20%), such as fish oil. Recently, through electroporation-induced mutation, a high-DHA-content strain of Schizochytrium sp. GCD2032 was isolated. To further enhance its DHA production, optimizations were conducted on the culture medium and fermentation conditions (in shaking flasks), as well as different nitrogen source concentrations (in a 5 L fermenter) for biomass, fatty acid content, and DHA content (as a percentage of total fatty acids). In a 5 L fermenter, Schizochytrium sp. GCD2032 achieved a biomass of 50 g/L, with fatty acid content of 55.71% and DHA content of 61.29%. Notably, the DHA content reached an impressive 341.45 mg/g of dry weight. This strain consistently produces high levels of fatty acids and DHA, demonstrating significant potential for pharmaceutical applications. Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control: 2nd Edition)

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15 pages, 1688 KiB

Open AccessArticle

Assessing Waste Sunflower Oil as a Substrate for Citric Acid Production: The Inhibitory Effect of Triton X-100

by Bilge Sayın, Akif Göktuğ Bozkurt and Güzin Kaban

Fermentation 2024, 10(7), 374; https://doi.org/10.3390/fermentation10070374 - 22 Jul 2024

Viewed by 1688

Abstract

In this study, waste sunflower oils were evaluated as substrates for citric acid (CA) production by Yarrowia lipolytica IFP29 (ATCC 20460). This strain was selected based on its capacity to produce organic acids in a selective medium. Attempts were made to optimize the [...] Read more.

In this study, waste sunflower oils were evaluated as substrates for citric acid (CA) production by Yarrowia lipolytica IFP29 (ATCC 20460). This strain was selected based on its capacity to produce organic acids in a selective medium. Attempts were made to optimize the process using the Taguchi statistical method in terms of the oil polarity, oil concentration, fermentation time, and Triton X-100 concentration. The results indicated that Y. lipolytica IFP29 utilized waste sunflower oil as a substrate and produced a maximum CA of 32.17 ± 1.44 g/L. Additionally, Triton X-100 inhibited the production of CA. For this reason, this process could not be optimized. These results were obtained by periodically adjusting the pH with NaOH during the fermentation period. On the other hand, a new experimental design was created without Triton X-100. As a buffering agent, 2-morpholinoethanesulfonic acid monohydrate (MES) was used to prevent a drop in pH; the maximum concentration of CA was found to be 20.31 ± 2.76. The optimum conditions were as follows: 90 g/L of waste sunflower oil with a polarity of 16 and 12 days of fermentation. According to the analysis of variance results, the effects of factors other than polarity on CA production were found to be significant (p < 0.05). Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control: 2nd Edition)

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15 pages, 4552 KiB

Open AccessArticle

Online Monitoring of the Temperature and Relative Humidity of Recycled Bedding for Dairy Cows on Dairy Farms

by Yong Wei, Kun Liu, Yaao Li, Zhixing Li, Tianyu Zhao, Pengfei Zhao, Yayin Qi, Meiying Li and Zongyuan Wang

Fermentation 2024, 10(7), 346; https://doi.org/10.3390/fermentation10070346 - 1 Jul 2024

Viewed by 1460

Abstract

In large-scale dairy farming, the use of high-temperature-fermented dairy manure bedding instead of rice husk-based bedding and other commercial types of bedding is widely favored. Strip-stacking aerobic fermentation is the main production method of dairy manure bedding, but it has problems including unstable [...] Read more.

In large-scale dairy farming, the use of high-temperature-fermented dairy manure bedding instead of rice husk-based bedding and other commercial types of bedding is widely favored. Strip-stacking aerobic fermentation is the main production method of dairy manure bedding, but it has problems including unstable fermentation and the secondary breeding of pathogens. In this work, a multi-probe, integrated, online monitoring system for temperature and relative humidity was used for fermentation process optimization. The effects of the temporal and spatial distribution of fermentation temperature and relative humidity on the nutrient content curve and the moisture and ash content of manure bedding materials were systematically studied. The effect of the fermentation process on the retention rate of effective bedding materials (cellulose, hemicellulose, and lignin) was analyzed. The experiments proved that high-quality bedding material can be obtained through reasonable stacking fermentation. The fabricated bedding material has a total dry base content consisting of cellulose, hemicellulose, and lignin of 78%, an ash content of 6%, and a nutrient content of 17%. The obtained bedding material was produced to increase the bed rest rate and continuously inhibit the bedding bacteria content, keeping it at a low level for 5 days. This study proves that temperature and humidity monitoring can guide the optimization of the strip-stacking fermentation process of dairy manure and that it can be applied to large-scale farms to improve fermentation parameters. Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control: 2nd Edition)

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