Fermentation

Research

Jump to: Review

17 pages, 4458 KiB

Open AccessArticle

Towards Sustainable Bioinoculants: A Fermentation Strategy for High Cell Density Cultivation of Paraburkholderia sp. SOS3, a Plant Growth-Promoting Bacterium Isolated in Queensland, Australia

by Ian Petersen, Chanyarat Paungfoo-Lonhienne, Esteban Marcellin, Lars Keld Nielsen and Axayacatl Gonzalez

Fermentation 2021, 7(2), 58; https://doi.org/10.3390/fermentation7020058 - 9 Apr 2021

Cited by 5 | Viewed by 3468

Abstract

Paraburkholderia sp. SOS3 is a plant growth-promoting bacterium (PGPB) that displays pleiotropic effects and has the potential to be applied at a large scale across several agronomically important crops. The use of SOS3 is a suitable option to reduce the use of chemical [...] Read more.

Paraburkholderia sp. SOS3 is a plant growth-promoting bacterium (PGPB) that displays pleiotropic effects and has the potential to be applied at a large scale across several agronomically important crops. The use of SOS3 is a suitable option to reduce the use of chemical fertilisers. While the benefits of SOS3 have been demonstrated in vitro, its potential applications at large scale are limited due to low biomass yield in current batch culture systems. Here, we developed a strategy for high-cell density cultivation of SOS3 in instrumented bioreactors, moving from low-biomass yield in a complex medium to high-biomass yield in a semi-defined medium. We achieved a 40-fold increase in biomass production, achieving cell densities of up to 11 g/L (OD₆₀₀ = 40). This result was achieved when SOS3 was cultivated using a fed-batch strategy. Biomass productivity, initially 0.02 g/L/h in batch cultures, was improved 12-fold, reaching 0.24 g/L/h during fed-batch cultures. The biomass yield was also improved 10-fold from 0.07 to 0.71 g_biomass/g_solids. Analysis of the fermentation profile of SOS3 indicated minimal production of by-products and accumulation of polyhydroxybutyrate (PHB) during the exponential growth phase associated with nitrogen limitation in the medium. By implementing proteomics analysis in fed-batch cultures, we identified the expression of four metabolic pathways associated with growth-promoting effects, which may be used as a qualitative parameter to guarantee the efficacy of SOS3 when used as a bioinoculant. Ultimately, we confirmed that the high-cell density cultures maintained their plant growth-promoting capacity when tested in sorghum and maize under glasshouse conditions. Full article

(This article belongs to the Special Issue Biorefineries)

► Show Figures

Graphical abstract

22 pages, 5497 KiB

Open AccessArticle

Dynamic Co-Cultivation Process of Corynebacterium glutamicum Strains for the Fermentative Production of Riboflavin

by Fernando Pérez-García, Arthur Burgardt, Dina R. Kallman, Volker F. Wendisch and Nadav Bar

Fermentation 2021, 7(1), 11; https://doi.org/10.3390/fermentation7010011 - 12 Jan 2021

Cited by 12 | Viewed by 4134

Abstract

Residual streams from lignocellulosic processes contain sugar mixtures of glucose, xylose, and mannose. Here, the industrial workhorse Corynebacterium glutamicum was explored as a research platform for the rational utilization of a multiple sugar substrate. The endogenous manA gene was overexpressed to enhance mannose [...] Read more.

Residual streams from lignocellulosic processes contain sugar mixtures of glucose, xylose, and mannose. Here, the industrial workhorse Corynebacterium glutamicum was explored as a research platform for the rational utilization of a multiple sugar substrate. The endogenous manA gene was overexpressed to enhance mannose utilization. The overexpression of the xylA gene from Xanthomonas campestris in combination with the endogenous xylB gene enabled xylose consumption by C. glutamicum. Furthermore, riboflavin production was triggered by overexpressing the sigH gene from C. glutamicum. The resulting strains were studied during batch fermentations in flasks and 2 L lab-scale bioreactors separately using glucose, mannose, xylose, and a mixture of these three sugars as a carbon source. The production of riboflavin and consumption of sugars were improved during fed-batch fermentation thanks to a dynamic inoculation strategy of manA overexpressing strain and xylAB overexpressing strain. The final riboflavin titer, yield, and volumetric productivity from the sugar mixture were 27 mg L⁻¹, 0.52 mg g⁻¹, and 0.25 mg L⁻¹ h⁻¹, respectively. It reached a 56% higher volumetric productivity with 45% less by-product formation compared with an equivalent process inoculated with a single strain overexpressing the genes xylAB and manA combined. The results indicate the advantages of dynamic multi strains processes for the conversion of sugar mixtures. Full article

(This article belongs to the Special Issue Biorefineries)

► Show Figures

Figure 1

10 pages, 323 KiB

Open AccessArticle

Valorization of Value-Added Resources from the Anaerobic Digestion of Swine-Raising Manure for Circular Economy in Taiwan

by Yu-Ru Lee and Wen-Tien Tsai

Fermentation 2020, 6(3), 81; https://doi.org/10.3390/fermentation6030081 - 7 Aug 2020

Cited by 9 | Viewed by 2961

Abstract

Due to the benefits of mitigating greenhouse gas emission and upgrading farmland fertilization, the valorization of liquor and biogas digestate from the anaerobic digestion of swine manure has attracted much attention in recent years. This article is based on the updated data/information from [...] Read more.

Due to the benefits of mitigating greenhouse gas emission and upgrading farmland fertilization, the valorization of liquor and biogas digestate from the anaerobic digestion of swine manure has attracted much attention in recent years. This article is based on the updated data/information from the official websites for summarizing the status of the swine-raising industry and innovative manure management, relevant sustainable development indicators, and inter-ministry promotion regulations in Taiwan. The survey findings revealed that the carbon dioxide emission reduction in 2019 was equivalent to about 36,000 metric tons based on a total of 2.35 million metric tons liquor and biogas digestate applied and 2 million swine heads for the biogas-to-power. Obviously, the regulatory measures by the Council of Agriculture, the Environmental Protection Administration, and the Ministry of Economic Affairs have provided economic and financial supports towards the reduction of 67.39 × 10³ metric tons carbon dioxide equivalent by 2030. Using the principles of biorefinery and zero-waste, the integration of anaerobic digestion, by-products (liquor and digestate), and biogas-to-power for treating swine manure is a win-win-win option for environmental, energy, and economic benefits. Full article

(This article belongs to the Special Issue Biorefineries)

► Show Figures

Figure 1

12 pages, 3420 KiB

Open AccessArticle

Simulation and Performance Analysis of Integrated Gasification–Syngas Fermentation Plant for Lignocellulosic Ethanol Production

by Sahar Safarian, Runar Unnthorsson and Christiaan Richter

Fermentation 2020, 6(3), 68; https://doi.org/10.3390/fermentation6030068 - 14 Jul 2020

Cited by 19 | Viewed by 7092

Abstract

This study presents a new simulation model developed with ASPEN Plus of waste biomass gasification integrated with syngas fermentation and product recovery units for bioethanol production from garden waste as a lignocellulosic biomass. The simulation model includes three modules: gasification, fermentation, and ethanol [...] Read more.

This study presents a new simulation model developed with ASPEN Plus of waste biomass gasification integrated with syngas fermentation and product recovery units for bioethanol production from garden waste as a lignocellulosic biomass. The simulation model includes three modules: gasification, fermentation, and ethanol recovery. A parametric analysis is carried out to investigate the effect of gasification temperature (500–1500 °C) and equivalence ratio (0.2–0.6) on the gasification performance and bioethanol production yield. The results reveal that, for efficient gasification and high ethanol production, the operating temperature range should be 700–1000 °C, as well as an equivalence ratio between 0.2 and 0.4. At optimal operating conditions, the bioethanol production yield is 0.114 kg/h per 1 kg/h input garden waste with 50% moisture content. It is worth mentioning that this parameter increases to 0.217 kg_bioethanol/kg_{garden waste} under dry-based conditions. Full article

(This article belongs to the Special Issue Biorefineries)

► Show Figures

Figure 1

14 pages, 1930 KiB

Open AccessArticle

Increased Selectivity for Butanol in Clostridium Pasteurianum Fermentations via Butyric Acid Addition or Dual Feedstock Strategy

by Garret Munch, Justus Mittler and Lars Rehmann

Fermentation 2020, 6(3), 67; https://doi.org/10.3390/fermentation6030067 - 9 Jul 2020

Cited by 5 | Viewed by 2818

Abstract

Volatility of the petroleum market has renewed research into butanol as an alternate fuel. In order to increase the selectivity for butanol during glycerol fermentation with Clostridium pasteurianum, butyric acid can be added to the medium. In this manuscript, different methods of [...] Read more.

Volatility of the petroleum market has renewed research into butanol as an alternate fuel. In order to increase the selectivity for butanol during glycerol fermentation with Clostridium pasteurianum, butyric acid can be added to the medium. In this manuscript, different methods of extracellular butyric acid addition are explored, as well as self-generation of butyric acid fermented from sugars in a co-substrate strategy. Molasses was used as an inexpensive sugar substrate, and the optimal molasses to glycerol ratio was found to allow the butyric acid to be taken back up into the cells and increase the productivity of butanol from all carbon sources. When butyric acid is added directly into the media, there was no significant difference between chemically pure butyric acid, or butyric acid rich supernatant from a separate fermentation. When low concentrations of butyric acid (1 or 2 g/L) are added to the initial media, an inhibitory effect is observed, with no influence on the butanol selectivity. However, when added later to the fermentation, over 1 g/L butyric acid is taken into the cells and increased the relative carbon yield from 0.449 to 0.519 mols carbon in product/mols carbon in substrate. An optimized dual substrate fermentation strategy in a pH-controlled reactor resulted in the relative carbon yield rising from 0.439 when grown on solely glycerol, to 0.480 mols C product/mols C substrate with the dual substrate strategy. An additional benefit is the utilization of a novel source of sugars to produce butanol from C. pasteurianum. The addition of butyric acid, regardless of how it is generated, under the proper conditions can allow for increased selectivity for butanol from all substrates. Full article

(This article belongs to the Special Issue Biorefineries)

► Show Figures

Figure 1

15 pages, 1353 KiB

Open AccessArticle

Steam Explosion Pretreatment of Sludge for Pharmaceutical Removal and Heavy Metal Release to Improve Biodegradability and Biogas Production

by Abolfazl Lotfi Aski, Alimohammad Borghei, Ali Zenouzi, Nariman Ashrafi and Mohammad J. Taherzadeh

Fermentation 2020, 6(1), 34; https://doi.org/10.3390/fermentation6010034 - 20 Mar 2020

Cited by 7 | Viewed by 3520

Abstract

Steam explosion pretreatment was developed and evaluated to remove pharmaceuticals and heavy metals from wastewater sludge and to improve its biodegradability and methane yield. Effects of pressure (5–15 bar) and duration (1–15 min) during the pretreatment were examined, and the pretreatment efficiency was [...] Read more.

Steam explosion pretreatment was developed and evaluated to remove pharmaceuticals and heavy metals from wastewater sludge and to improve its biodegradability and methane yield. Effects of pressure (5–15 bar) and duration (1–15 min) during the pretreatment were examined, and the pretreatment efficiency was evaluated based on the solubilization degree, the capillary suction time (CST) test and anaerobic digestion. The removal efficiency of ibuprofen, acetaminophen, and amoxicillin was 65%, 69%, and 66% and 70%, 66%, and 70% in primary sludge (PS) and waste-activated sludge (WAS), respectively. The highest percent release efficiency of heavy metals, i.e., lead, cadmium, and silver, for PS and WAS was 78%, 70%, and 79% and 79%, 80%, and 75%, respectively. The highest methane yield was obtained after pretreatment at 10 bar for 15 min and at 15 bar for 10 min, with respective yields of 380 and 358 mL CH₄/g volatile solids (VS) for the PS and 315 and 334 mL CH₄/g VS for the WAS. The results of methane production indicated that the decreased concentrations of pharmaceuticals and heavy metals resulted in increased biodegradability of PS and WAS. Full article

(This article belongs to the Special Issue Biorefineries)

► Show Figures

Figure 1

Review

Jump to: Research

31 pages, 5140 KiB

Open AccessReview

A Comprehensive Understanding of Electro-Fermentation

by Drishti Dinesh Bhagchandanii, Rishi Pramod Babu, Jayesh M. Sonawane, Namita Khanna, Soumya Pandit, Dipak A. Jadhav, Santimoy Khilari and Ram Prasad

Fermentation 2020, 6(3), 92; https://doi.org/10.3390/fermentation6030092 - 21 Sep 2020

Cited by 52 | Viewed by 12279

Abstract

Electro-fermentation (EF) is an upcoming technology that can control the metabolism of exoelectrogenic bacteria (i.e., bacteria that transfer electrons using an extracellular mechanism). The fermenter consists of electrodes that act as sink and source for the production and movement of electrons and protons, [...] Read more.

Electro-fermentation (EF) is an upcoming technology that can control the metabolism of exoelectrogenic bacteria (i.e., bacteria that transfer electrons using an extracellular mechanism). The fermenter consists of electrodes that act as sink and source for the production and movement of electrons and protons, thus generating electricity and producing valuable products. The conventional process of fermentation has several drawbacks that restrict their application and economic viability. Additionally, metabolic reactions taking place in traditional fermenters are often redox imbalanced. Almost all metabolic pathways and microbial strains have been studied, and EF can electrochemically control this. The process of EF can be used to optimize metabolic processes taking place in the fermenter by controlling the redox and pH imbalances and by stimulating carbon chain elongation or breakdown to improve the overall biomass yield and support the production of a specific product. This review briefly discusses microbe-electrode interactions, electro-fermenter designs, mixed-culture EF, and pure culture EF in industrial applications, electro methanogenesis, and the various products that could be hence generated using this process. Full article

(This article belongs to the Special Issue Biorefineries)

► Show Figures

Figure 1

18 pages, 1234 KiB

Open AccessReview

Valorising Agro-industrial Wastes within the Circular Bioeconomy Concept: the Case of Defatted Rice Bran with Emphasis on Bioconversion Strategies

by Maria Alexandri, José Pablo López-Gómez, Agata Olszewska-Widdrat and Joachim Venus

Fermentation 2020, 6(2), 42; https://doi.org/10.3390/fermentation6020042 - 22 Apr 2020

Cited by 34 | Viewed by 10114

Abstract

The numerous environmental problems caused by the extensive use of fossil resources have led to the formation of the circular bioeconomy concept. Renewable resources will constitute the cornerstone of this new, sustainable model, with biomass presenting a huge potential for the production of [...] Read more.

The numerous environmental problems caused by the extensive use of fossil resources have led to the formation of the circular bioeconomy concept. Renewable resources will constitute the cornerstone of this new, sustainable model, with biomass presenting a huge potential for the production of fuels and chemicals. In this context, waste and by-product streams from the food industry will be treated not as “wastes” but as resources. Rice production generates various by-product streams which currently are highly unexploited, leading to environmental problems especially in the countries that are the main producers. The main by-product streams include the straw, the husks, and the rice bran. Among these streams, rice bran finds applications in the food industry and cosmetics, mainly due to its high oil content. The high demand for rice bran oil generates huge amounts of defatted rice bran (DRB), the main by-product of the oil extraction process. The sustainable utilisation of this by-product has been a topic of research, either as a food additive or via its bioconversion into value-added products and chemicals. This review describes all the processes involved in the efficient bioconversion of DRB into biotechnological products. The detailed description of the production process, yields and productivities, as well as strains used for the production of bioethanol, lactic acid and biobutanol, among others, are discussed. Full article

(This article belongs to the Special Issue Biorefineries)

► Show Figures

Figure 1

11 pages, 652 KiB

Open AccessReview

Production of the Polysaccharide Curdlan by Agrobacterium species on Processing Coproducts and Plant Lignocellulosic Hydrolysates

by Thomas P. West

Fermentation 2020, 6(1), 16; https://doi.org/10.3390/fermentation6010016 - 24 Jan 2020

Cited by 27 | Viewed by 4153

Abstract

This review examines the production of the biopolymer curdlan, synthesized by Agrobacterium species (sp.), on processing coproducts and plant lignocellulosic hydrolysates. Curdlan is a β-(1→3)-D-glucan that has various food, non-food and biomedical applications. A number of carbon sources support bacterial curdlan production upon [...] Read more.

This review examines the production of the biopolymer curdlan, synthesized by Agrobacterium species (sp.), on processing coproducts and plant lignocellulosic hydrolysates. Curdlan is a β-(1→3)-D-glucan that has various food, non-food and biomedical applications. A number of carbon sources support bacterial curdlan production upon depletion of nitrogen in the culture medium. The influence of culture medium pH is critical to the synthesis of curdlan. The biosynthesis of the β-(1→3)-D-glucan is likely controlled by a regulatory protein that controls the genes involved in the bacterial production of curdlan. Curdlan overproducer mutant strains have been isolated from Agrobacterium sp. ATCC 31749 and ATCC 31750 by chemical mutagenesis and different selection procedures. Several processing coproducts of crops have been utilized to support the production of curdlan. Of the processing coproducts investigated, cassava starch waste hydrolysate as a carbon source or wheat bran as a nitrogen source supported the highest curdlan production by ATCC 31749 grown at 30 °C. To a lesser extent, plant biomass hydrolysates have been explored as possible substrates for curdlan production by ATCC 31749. Prairie cordgrass hydrolysates have been shown to support curdlan production by ATCC 31749 although a curdlan overproducer mutant strain, derived from ATCC 31749, was shown to support nearly double the level of ATCC 31749 curdlan production under the same growth conditions. Full article

(This article belongs to the Special Issue Biorefineries)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Biorefineries

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (9 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI