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16 pages, 4574 KiB

Open AccessArticle

A Novel Extracellular Catalase Produced by the Antarctic Filamentous Fungus Penicillium Rubens III11-2

by Zdravka Koleva, Radoslav Abrashev, Maria Angelova, Galina Stoyancheva, Boryana Spassova, Lyudmila Yovchevska, Vladislava Dishliyska, Jeny Miteva-Staleva and Ekaterina Krumova

Fermentation 2024, 10(1), 58; https://doi.org/10.3390/fermentation10010058 - 15 Jan 2024

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Abstract

Catalase (CAT) is an enzyme involved in the first line of cellular antioxidant defense. It plays a key role in the protection of a wide range of Antarctic organisms against cold stress. Extracellular catalase is very rare and data on it are extremely [...] Read more.

Catalase (CAT) is an enzyme involved in the first line of cellular antioxidant defense. It plays a key role in the protection of a wide range of Antarctic organisms against cold stress. Extracellular catalase is very rare and data on it are extremely scarce. The aim of the present study was to select an efficient producer of extracellular catalase from amongst Antarctic filamentous fungi. Sixty-two Antarctic filamentous fungal strains were investigated for their potential ability to synthesize intracellular and extracellular CAT. The Antarctic strain Penicillium rubens III11-2 was selected as the best producer of extracellular catalase. New information on the involvement of the extracellular antioxidant enzymes superoxide dismutase and CAT in the response of filamentous fungi against low-temperature stress was obtained. An efficient scheme for the purification of CAT from culture fluid was developed. An enzyme preparation with high specific activity (513 U/mg protein) was obtained with a yield of 19.97% and a purification rate of 98.4-fold. The purified enzyme exhibited maximal enzymatic activity in the temperature range of 5–40 °C and temperature stability between 0 and 30 °C, therefore being characterized as temperature sensitive. To our knowledge, this is the first purified extracellular cold active catalase preparation from Antarctic filamentous fungi. Full article

(This article belongs to the Special Issue New Research on Strains Improvement and Microbial Biosynthesis)

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13 pages, 5788 KiB

Open AccessArticle

A Physiogenomic Study of the Tolerance of Saccharomyces cerevisiae to Isoamyl Alcohol

by Jialin Song, Yu Wang, Hengyuan Xu, Jinshang Liu, Jianping Wang, Haojun Zhang and Cong Nie

Fermentation 2024, 10(1), 4; https://doi.org/10.3390/fermentation10010004 - 20 Dec 2023

Viewed by 1146

Abstract

Isoamyl alcohol is a clear, unpleasantly odorous, colorless liquid of higher alcohol that emits a fruity aroma when heavily diluted. It has received much attention in recent years as a new fuel with a high energy density. Isoamyl alcohol can be produced industrially [...] Read more.

Isoamyl alcohol is a clear, unpleasantly odorous, colorless liquid of higher alcohol that emits a fruity aroma when heavily diluted. It has received much attention in recent years as a new fuel with a high energy density. Isoamyl alcohol can be produced industrially by microbial fermentation. Still, its toxicity to host cells has limited its potential for industrial production, and the molecular mechanism of its toxic effects has not yet been elucidated. In this study, RNA-Seq technology was used to analyze the transcripts of Saccharomyces cerevisiae under normal conditions and in the presence of isoamyl alcohol (0.5 g/L and 2.5 g/L). The results showed that the expression of the cell wall (CCW12, BGL2, NCW2 and SUN4), cell membrane (ELO1, ERG2, FAA1, and OPI3), translation and other structural genes were significantly down-regulated. The expression of genes related to ATP biosynthesis, NADPH biosynthesis (ZWF1), and metal ion transport (PMC1) proteins were up-regulated. Strains with key genes knocked out were cultured without isoamyl alcohol. Combined results suggested that isoamyl alcohol may affect cell wall stability and cell membrane fluidity, and the expression of genes related to ion homeostasis and energy production may play a protective role against isoamyl alcohol stress. By maintaining cell wall stability/membrane fluidity under isoamyl alcohol pressure, improving certain ion homeostasis, and generating energy/NADPH, it is possible to overcome the toxicity of isoamyl alcohol in industrial fermentation processes to a certain extent. Full article

(This article belongs to the Special Issue New Research on Strains Improvement and Microbial Biosynthesis)

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25 pages, 2502 KiB

Open AccessArticle

Screening Bacterial Strains Capable of Producing 2,3-Butanediol: Process Optimization and High Diol Production by Klebsiella oxytoca FMCC-197

by Anastasia Marina Palaiogeorgou, Ermis Ioannis Michail Delopoulos, Apostolis A. Koutinas and Seraphim Papanikolaou

Fermentation 2023, 9(12), 1014; https://doi.org/10.3390/fermentation9121014 - 12 Dec 2023

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Abstract

In the present investigation, the potential of various newly isolated strains which belong to the Enterobacteriaceae family to produce 2,3-butanediol (BDO), an important bio-based compound, was studied. The most interesting strain, namely Klebsiella oxytoca FMCC-197, was selected for further investigation. Commercial (raw) sucrose [...] Read more.

In the present investigation, the potential of various newly isolated strains which belong to the Enterobacteriaceae family to produce 2,3-butanediol (BDO), an important bio-based compound, was studied. The most interesting strain, namely Klebsiella oxytoca FMCC-197, was selected for further investigation. Commercial (raw) sucrose or molasses, which are important agro-industrial surpluses, were employed as carbon sources for most of the trials performed. Different fermentation parameters (viz. incubation te4mperature, utilization of different carbon sources, substrate inhibition, aeration) were tested to optimize the process. Fermentations under non-aseptic conditions were also conducted to investigate the potential of growth of the strain K. oxytoca FMCC-197 to surpass the growth of other microorganisms in the culture medium and produce BDO. Besides BDO production, in trials in which molasses was employed as the sole carbon source, significant color removal was observed simultaneously with the production of microbial metabolites. The very high BDO concentration ≈115 g L⁻¹ was reported in approximately 64 h during a fed-batch bioreactor experiment, using sucrose and molasses as carbon sources at 30 °C, reaching a conversion yield (Y_BDO) of 0.40 g g⁻¹ and a productivity rate (P_BDO) of 1.80 g L⁻¹ h⁻¹, while similar results were also obtained at 37 °C. The strain demonstrated remarkable results in non-previously sterilized media, as it produced 58.0 g L⁻¹ in 62 h during a fed-batch bioreactor experiment, while the potential to decolorize molasses-based substrates over 40% was also recorded. From the results obtained it is shown that this wild-type strain can be used in large-scale microbial BDO production using various raw materials as fermentative substrates. The wastewater derived after BDO fermentation by K. oxytoca FMCC-197 can be disposed relatively safely into the environment. Full article

(This article belongs to the Special Issue New Research on Strains Improvement and Microbial Biosynthesis)

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15 pages, 7839 KiB

Open AccessArticle

Whole-Genome Analysis of Novacetimonas cocois and the Effects of Carbon Sources on Synthesis of Bacterial Cellulose

by Yujuan Zheng, Min Chen, Jiaxin Li, Shuangwen Fei, Shuai Shang, Sixin Liu, Longxiang Liu and Congfa Li

Fermentation 2023, 9(11), 972; https://doi.org/10.3390/fermentation9110972 - 14 Nov 2023

Viewed by 1029

Abstract

Novacetimonas cocois WE7 (formally named Komagataeibacter cocois WE7) is a strain isolated from contaminated coconut milk, capable of producing bacterial cellulose (BC). We sequenced its genome to investigate why WE7 cannot synthesize BC from glucose efficiently. It contains about 3.5 Mb and six [...] Read more.

Novacetimonas cocois WE7 (formally named Komagataeibacter cocois WE7) is a strain isolated from contaminated coconut milk, capable of producing bacterial cellulose (BC). We sequenced its genome to investigate why WE7 cannot synthesize BC from glucose efficiently. It contains about 3.5 Mb and six plasmid DNAs. N. cocois WE7 contains two bcs operons (bacterial cellulose operon, bcs I and bcs II); the absence of bcs III operons may lead to reduced BC production. From genome predictions, glucose, sucrose, fructose, maltose, and glycerol can be utilized to generate BC, with WE7 unable to metabolize carbohydrate carbon sources through the Embden–Meyerhof–Parnas (EMP) pathway, but rather through the Hexose Monophosphate Pathway (HMP) and tricarboxylic acid (TCA) pathways. It has a complete gluconic acid production pathway, suggesting that BC yield might be very low when glucose, maltose, and trehalose are used as carbon sources. This study represents the first genome analysis of N. cocois. This information is crucial for understanding BC production and regulation mechanisms in N. cocois and lays a foundation for constructing engineered strains tailored for diverse BC application purposes. Full article

(This article belongs to the Special Issue New Research on Strains Improvement and Microbial Biosynthesis)

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15 pages, 6846 KiB

Open AccessArticle

Effects of Aromatic Compounds Degradation on Bacterial Cell Morphology

by Maria Gerginova, Gulzhan Spankulova, Tsvetelina Paunova-Krasteva, Nadejda Peneva, Stoyanka Stoitsova and Zlatka Alexieva

Fermentation 2023, 9(11), 957; https://doi.org/10.3390/fermentation9110957 - 08 Nov 2023

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Abstract

The aim of the present study was to evaluate in parallel the capacity of three bacterial strains originating from oil-polluted soils to degrade monoaromatic compounds and the alterations in the bacterial cell morphology as a result of the biodegradation. The strain Gordonia sp. [...] Read more.

The aim of the present study was to evaluate in parallel the capacity of three bacterial strains originating from oil-polluted soils to degrade monoaromatic compounds and the alterations in the bacterial cell morphology as a result of the biodegradation. The strain Gordonia sp. 12/5 can grow well in media containing catechol, o-, m-, and p-cresol without significant morphological changes in the cells, as shown by scanning electron microscopy. This implies good adaptation of the strain for growth in hydrocarbon-containing media and indicates it is a proper candidate strain for further development of purification methodologies applicable to ecosystems contaminated with such compounds. The growth of the two Rhodococcus strains in the presence of the above carbon sources is accompanied by changes in cell size characteristic of stress conditions. Nevertheless, their hydrocarbon-degrading capacity should not be neglected for future applications. In summary, the established ability to degrade monoaromatic compounds, in parallel with the morphological changes of the bacterial cells, can be used as a valuable indicator of the strain’s vitality in the presence of tested aromatic compounds and, accordingly, of its applicability for bioremediation purposes. Full article

(This article belongs to the Special Issue New Research on Strains Improvement and Microbial Biosynthesis)

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Review

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18 pages, 811 KiB

Open AccessReview

An Update on Microbial Biosynthesis of β-Caryophyllene, a Sesquiterpene with Multi-Pharmacological Properties

by Lidia Tsigoriyna, Chakarvati Sango and Daniela Batovska

Fermentation 2024, 10(1), 60; https://doi.org/10.3390/fermentation10010060 - 15 Jan 2024

Viewed by 1249

Abstract

The sesquiterpene β-caryophyllene (BCP) is a major component of various plant essential oils, to which it confers a unique spicy aroma. It is mainly used as a fragrance additive in the food, cosmetic and perfume industries, with an annual consumption ranging between 100 [...] Read more.

The sesquiterpene β-caryophyllene (BCP) is a major component of various plant essential oils, to which it confers a unique spicy aroma. It is mainly used as a fragrance additive in the food, cosmetic and perfume industries, with an annual consumption ranging between 100 and 1000 metric tons worldwide. Recently, BCP has attracted attention as a promising precursor for the production of high-density fuels and for its various biological activities and pharmacological effects. These include antioxidant, anti-inflammatory, anticancer, immune–modulatory, and many other activities. Due to its underlying mechanisms, β-caryophyllene interacts with various human receptors, including CB2 of the endocannabinoid system, which defines it as a phytocannabinoid with therapeutic potential for certain serious conditions. Due to β-caryophyllene’s high utility, various green and sustainable strategies for its production in microorganisms have been developed. This article provides an update on the state-of-the-art in this field to identify directions for further development to extend the compound’s potential. Full article

(This article belongs to the Special Issue New Research on Strains Improvement and Microbial Biosynthesis)

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34 pages, 1136 KiB

Open AccessReview

Cloning Systems in Bacillus: Bioengineering of Metabolic Pathways for Valuable Recombinant Products

by Alexander Arsov, Nadya Armenova, Emanoel Gergov, Kaloyan Petrov and Penka Petrova

Fermentation 2024, 10(1), 50; https://doi.org/10.3390/fermentation10010050 - 09 Jan 2024

Viewed by 1943

Abstract

Representatives of the genus Bacillus have been established as one of the most important industrial microorganisms in the last few decades. Genetically modified B. subtilis and, to a lesser extent, B. licheniformis, B. amyloliquefaciens, and B. megaterium have been used for [...] Read more.

Representatives of the genus Bacillus have been established as one of the most important industrial microorganisms in the last few decades. Genetically modified B. subtilis and, to a lesser extent, B. licheniformis, B. amyloliquefaciens, and B. megaterium have been used for the heterologous expression of numerous proteins (enzymes, vaccine components, growth factors), platform chemicals, and other organic compounds of industrial importance. Vectors designed to work in Bacillus spp. have dramatically increased in number and complexity. Today, they provide opportunities for genetic manipulation on every level, from point mutations to systems biology, that were impossible even ten years ago. The present review aims to describe concisely the latest developments in the shuttle, integrative, and CRISPR-Cas9 vectors in Bacillus spp. as well as their application for large-scale bioengineering with the prospect of producing valuable compounds on an industrial scale. Genetic manipulations of promoters and vectors, together with their impact on secretory and metabolic pathways, are discussed in detail. Full article

(This article belongs to the Special Issue New Research on Strains Improvement and Microbial Biosynthesis)

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14 pages, 1164 KiB

Open AccessReview

Symbiosis Mechanism of Associated Bacteria on 2-keto-L-gulonic Acid Production via Mixed Fermentation: A Review

by Wenhu Chen, Qian Liu, Meng Liu, Hongling Liu, Di Huang, Yi Jiang, Tengfei Wang and Haibo Yuan

Fermentation 2023, 9(12), 1000; https://doi.org/10.3390/fermentation9121000 - 25 Nov 2023

Viewed by 1249

Abstract

Vitamin C, a water-soluble vitamin with strong reducing power, cannot be synthesized by the human body and participates in a variety of important biochemical reactions. Vitamin C is widely used in the pharmaceutical, food, health care, beverage, cosmetics, and feed industries, with a [...] Read more.

Vitamin C, a water-soluble vitamin with strong reducing power, cannot be synthesized by the human body and participates in a variety of important biochemical reactions. Vitamin C is widely used in the pharmaceutical, food, health care, beverage, cosmetics, and feed industries, with a huge market demand. The classical two-step fermentation method is the mainstream technology for vitamin C production. D-sorbitol is transformed into L-sorbose by Gluconobacter oxydans in the first step of fermentation; then, L-sorbose is transformed into 2-keto-L-gulonic acid (2-KGA) by a coculture system composed of Ketogulonicigenium vulgare and associated bacteria; and finally, 2-KGA is transformed into vitamin C through chemical transformation. The conversion of L-sorbose into 2-KGA in the second fermentation step is performed by K. vulgare. However, considering the slow growth and low 2-KGA production of K. vulgare when cultured alone, it is necessary to add an associated bacteria to stimulate K. vulgare growth and 2-KGA production. Although the mechanism by which the associated bacteria promote K. vulgare growth and 2-KGA production has extensively been studied, this remains a hot topic in related fields. Based on the latest achievements and research, this review summarizes the metabolic characteristics of K. vulgare and associated bacteria and elucidates the mechanism by which the associated bacteria promote the growth and 2-KGA production of K. vulgare. Full article

(This article belongs to the Special Issue New Research on Strains Improvement and Microbial Biosynthesis)

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