Itaconic acid production from wheat chaff by Aspergillus terreus

Overcoming Challenges of Incorporation of Biobased Dibutyl Itaconate in (Meth)acrylic Waterborne Polymers

Polymeric derivatives of itaconic acid are gaining interest as biobased alternatives to petroleum-based monomers due to their versatility, renewable nature, commercial availability, and cost-effectiveness. Itaconate ester monomer's challenges incorporating in (meth)acrylic waterborne polymers are the low propagation rate, unfavorable reactivity ratios, and the depropagation process. To overcome these challenges, the seeded semibatch emulsion polymerization of 100% biobased dibutyl itaconate, methyl methacrylate, and butyl acrylate was investigated at different temperatures. Consequently, 30 wt % DBI was successfully incorporated within waterborne (meth)acrylates in short reaction times (4 h), obtaining high DBI incorporation (>90%). The results demonstrate that DBI incorporation influences the instantaneous monomer conversion, polymer's microstructure, and mechanical properties. By incorporating a biobased itaconate cross-linker, kinetics and mechanical characteristics of the polymers were improved. This combined approach can be implemented without altering industrial processes, resolving the commercialization dilemma for itaconate monomers to synthesize high-performance biobased polymers for adhesive and coating industries.

Biotechnological Utilization of Agro-Industrial Residues and By-Products-Sustainable Production of Biosurfactants

The importance and interest in the efficient use and valorization of agro-industrial residues and by-products have grown due to environmental problems associated with improper disposal. Biotechnological production processes, including microbial biosurfactant production, represent a sustainable way to utilize agro-industrial residues and by-products, which are applied as substrates in these processes. Biosurfactants produced by microorganisms using renewable resources are a viable alternative to traditional petrochemical surfactants and have several potential uses in a wide range of industrial sectors due to their minimal ecotoxicity, easy biodegradability, and moderate production conditions. The common applications of biosurfactants, besides in food industry as food additives and preservatives, are in agriculture, environmental protection, the cosmetics and pharmaceutical industry, wastewater treatment, the petroleum industry, etc. This review aims to summarize the comprehensive scientific research related to the use of various agro-industrial residues and by-products in the microbial production of biosurfactants, as well as to emphasize the present state and the importance of their sustainable production. Additionally, based on the available biosurfactant market analysis datasets and research studies, the current situation in science and industry and the future perspectives of microbial biosurfactant production have been discussed.

Utilization of sweet sorghum juice as a carbon source for enhancement of itaconic acid production in engineered Corynebacterium glutamicum

Itaconic acid is a promising biochemical building block that can be used in polymer synthesis. Itaconic acid is currently produced in industry by the natural producer fungus Aspergillus terreus using glucose as a main carbon source. Most research for itaconic acid production using lignocellulosic-based carbon sources was carried out by A. terreus. Engineered Corynebacterium glutamicum strain which can grow in presence of fermentation inhibitors without effect on growth, was used for production of itaconic acid using sweet sorghum juice and bagasse sugar lysate (BSL). BSL contains many inhibitors unlike sorghum juice. C. glutamicum could grow in the media containing both types of lignocellulose-based carbon sources without showing any growth inhibition, however, sorghum juice was better in itaconic acid production than BSL. Different constructed strains of C. glutamicum were used for itaconic acid production, however, C. glutamicum ATCC 13032 pCH-Tad1optAdi1opt strain expressing Adi1/Tad1 genes (trans-pathway) from Ustilago maydis proved to be better in itaconic acid production giving final titer of 8.4 and 4.02 g/L using sweet sorghum juice and BSL as the sole carbon sources by fed-batch fermentation. Our study is the first for production of itaconic acid using sweet sorghum juice and BSL. The present study also proved that C. glutamicum can be used for enhancing itaconic acid production using lignocellulosic-based carbon sources.

Microbial itaconic acid bioproduction towards sustainable development: Insights, challenges, and prospects

Microbial biomanufacturing is a promising approach to produce high-value compounds with low-carbon footprint and significant economic benefits. Among twelve "Top Value-Added Chemicals from Biomass", itaconic acid (IA) stands out as a versatile platform chemical with numerous applications. IA is naturally produced by Aspergillus and Ustilago species through a cascade enzymatic reaction between aconitase (EC 4.2.1.3) and cis-aconitic acid decarboxylase (EC 4.1.1.6). Recently, non-native hosts such as Escherichia coli, Corynebacterium glutamicum, Saccharomyces cerevisiae, and Yarrowia lipolytica have been genetically engineered to produce IA through the introduction of key enzymes. This review provides an up-to-date summary of the progress made in IA bioproduction, from native to engineered hosts, covers in vivo and in vitro approaches, and highlights the prospects of combination tactics. Current challenges and recent endeavors are also addressed to envision comprehensive strategies for renewable IA production in the future towards sustainable development goals (SDGs).

High-level itaconic acid (IA) production using engineered Escherichia coli Lemo21(DE3) toward sustainable biorefinery

Itaconic acid (IA) serves as a prominent building block for polyamides as sustainable material. In vivo IA production is facing the competing side reactions, byproducts accumulation, and long cultivation time. Therefore, the utilization of whole-cell biocatalysts to carry out production from citrate is an alternative approach to sidestep the current limitations. In this study, in vitro reaction of IA was obtained 72.44 g/L by using engineered E. coli Lemo21(DE3) harboring the aconitase (Acn, EC 4.2.1.3) and cis-aconitate decarboxylase (CadA, EC 4.1.1.6) which was cultured in glycerol-based minimal medium. IA productivity enhancement was observed after cold-treating the biocatalysts in - 80 °C for 24 h prior to the reaction, reaching 81.6 g/L. On the other hand, a new seeding strategy in Terrific Broth (TB) as a nutritionally rich medium was employed to maintain the biocatalysts stability up to 30 days. Finally, the highest IA titer of 98.17 g/L was attained using L21::7G chassis, that has a pLemo plasmid and integration of GroELS to the chromosome. The high-level of IA production along with the biocatalyst reutilization enables the economic viability toward a sustainable biorefinery.

Recent Advances on the Production of Itaconic Acid via the Fermentation and Metabolic Engineering

Itaconic acid (ITA) is one of the top 12 platform chemicals. The global ITA market is expanding due to the rising demand for bio-based unsaturated polyester resin and its non-toxic qualities. Although bioconversion using microbes is the main approach in the current industrial production of ITA, ecological production of bio-based ITA faces several issues due to: low production efficiency, the difficulty to employ inexpensive raw materials, and high manufacturing costs. As metabolic engineering advances, the engineering of microorganisms offers a novel strategy for the promotion of ITA bio-production. In this review, the most recent developments in the production of ITA through fermentation and metabolic engineering are compiled from a variety of perspectives, including the identification of the ITA synthesis pathway, the metabolic engineering of natural ITA producers, the design and construction of the ITA synthesis pathway in model chassis, and the creation, as well as application, of new metabolic engineering strategies in ITA production. The challenges encountered in the bio-production of ITA in microbial cell factories are discussed, and some suggestions for future study are also proposed, which it is hoped offers insightful views to promote the cost-efficient and sustainable industrial production of ITA.

Recent advances and perspectives on production of value-added organic acids through metabolic engineering

Organic acids are important consumable materials with a wide range of applications in the food, biopolymer and chemical industries. The global consumer organic acids market is estimated to increase to $36.86 billion by 2026. Conventionally, organic acids are produced from the chemical catalysis process with petrochemicals as raw materials, which posts severe environmental concerns and conflicts with our sustainable development goals. Most of the commonly used organic acids can be produced from various organisms. As a state-of-the-art technology, large-scale fermentative production of important organic acids with genetically-modified microbes has become an alternative to the chemical route to meet the market demand. Despite the fact that bio-based organic acid production from renewable cheap feedstock provides a viable solution, low productivity has impeded their industrial-scale application. With our deeper understanding of strain genetics, physiology and the availability of strain engineering tools, new technologies including synthetic biology, various metabolic engineering strategies, omics-based system biology tools, and high throughput screening methods are gradually established to bridge our knowledge gap. And they were further applied to modify the cellular reaction networks of potential microbial hosts and improve the strain performance, which facilitated the commercialization of consumable organic acids. Here we present the recent advances of metabolic engineering strategies to improve the production of important organic acids including fumaric acid, citric acid, itaconic acid, adipic acid, muconic acid, and we also discuss the current challenges and future perspectives on how we can develop a cost-efficient, green and sustainable process to produce these important chemicals from low-cost feedstocks.

Fumaric Acid Production by R. arrhizus NRRL 1526 Using Apple Pomace Enzymatic Hydrolysates: Kinetic Modelling

Fumaric acid is one of the most promising biorefinery platform chemicals, fruit residues being a very suitable raw material for its production in second generation biorefineries. In particular, apple pomace is a plentiful residue from the apple juice industry, with apple being the second largest fruit crop in the world, with a production that increased from 46 to 86 Mtons in the 1994–2021 period. With a global apple juice production of more than 4.5 Mtons, a similar amount of apple pomace is produced yearly. In this work, apple pomace hydrolysate has been obtained by enzymatic hydrolysis and further characterized for its content in sugars, phenolics and nitrogen using different analytic methods, based on HPLC and colorimetric techniques. Previous to the use of this hydrolysate (APH), we studied if the addition of fructose to the usual glucose-rich broth could lead to high fumaric acid yields, titers and productivities. Afterwards, APH fermentation was performed and improved using different nitrogen initial amounts, obtaining production yields (0.32 gFumaric acid/gconsumed sugar) similar to those obtained with synthetic media (0.38 gFumaric acid/gconsumed sugar). Kinetic modelling was employed to evaluate, explain, and understand the experimental values and trends of relevant components in the fermentation broth as functions of the bioprocess time, proposing a suitable reaction scheme and a non-structured, non-segregated kinetic model based on it.

John PC, Kumar N. Bayesian Inference for Integrating Yarrowia lipolytica Multiomics Datasets with Metabolic Modeling

Optimizing the metabolism of microbial cell factories for yields and titers is a critical step for economically viable production of bioproducts and biofuels. In this process, tuning the expression of individual enzymes to obtain the desired pathway flux is a challenging step, in which data from separate multiomics techniques must be integrated with existing biological knowledge to determine where changes should be made. Following a design-build-test-learn strategy, building on recent advances in Bayesian metabolic control analysis, we identify key enzymes in the oleaginous yeast Yarrowia lipolytica that correlate with the production of itaconate by integrating a metabolic model with multiomics measurements. To this extent, we quantify the uncertainty for a variety of key parameters, known as flux control coefficients (FCCs), needed to improve the bioproduction of target metabolites and statistically obtain key correlations between the measured enzymes and boundary flux. Based on the top five significant FCCs and five correlated enzymes, our results show phosphoglycerate mutase, acetyl-CoA synthetase (ACSm), carbonic anhydrase (HCO3E), pyrophosphatase (PPAm), and homoserine dehydrogenase (HSDxi) enzymes in rate-limiting reactions that can lead to increased itaconic acid production.

Consolidated bioprocessing of cellulose to itaconic acid by a co-culture of Trichoderma reesei and Ustilago maydis

BACKGROUND

Itaconic acid is a bio-derived platform chemical with uses ranging from polymer synthesis to biofuel production. The efficient conversion of cellulosic waste streams into itaconic acid could thus enable the sustainable production of a variety of substitutes for fossil oil based products. However, the realization of such a process is currently hindered by an expensive conversion of cellulose into fermentable sugars. Here, we present the stepwise development of a fully consolidated bioprocess (CBP), which is capable of directly converting recalcitrant cellulose into itaconic acid without the need for separate cellulose hydrolysis including the application of commercial cellulases. The process is based on a synthetic microbial consortium of the cellulase producer Trichoderma reesei and the itaconic acid producing yeast Ustilago maydis. A method for process monitoring was developed to estimate cellulose consumption, itaconic acid formation as well as the actual itaconic acid production yield online during co-cultivation.

RESULTS

The efficiency of the process was compared to a simultaneous saccharification and fermentation setup (SSF). Because of the additional substrate consumption of T. reesei in the CBP, the itaconic acid yield was significantly lower in the CBP than in the SSF. In order to increase yield and productivity of itaconic acid in the CBP, the population dynamics was manipulated by varying the inoculation delay between T. reesei and U. maydis. Surprisingly, neither inoculation delay nor inoculation density significantly affected the population development or the CBP performance. Instead, the substrate availability was the most important parameter. U. maydis was only able to grow and to produce itaconic acid when the cellulose concentration and thus, the sugar supply rate, was high. Finally, the metabolic processes during fed-batch CBP were analyzed in depth by online respiration measurements. Thereby, substrate availability was again identified as key factor also controlling itaconic acid yield. In summary, an itaconic acid titer of 34 g/L with a total productivity of up to 0.07 g/L/h and a yield of 0.16 g/g could be reached during fed-batch cultivation.

CONCLUSION

This study demonstrates the feasibility of consortium-based CBP for itaconic acid production and also lays the fundamentals for the development and improvement of similar microbial consortia for cellulose-based organic acid production.

Aspegillus terreus: From Soil to Industry and Back

Aspergillus terreus is an important saprophytic filamentous fungus that can be found in soils. Like many other soil microorganisms, A. terreus demonstrates multiple functions and offers various important metabolites, which can be used in different fields of human activity. The first application of A. terreus on an industrial level is the production of itaconic acid, which is now considered as one of the most important bioproducts in the Green Chemistry field. The general schemes for itaconic acid production have been studied, but in this mini-review some lines of future research are presented based on analysis of the published results. A. terreus is also intensively studied for its biocontrol activity and plant growth-promoting effect. However, this microorganism is also known to infect important crops such as, amongst others, rice, wheat, potato, sugar cane, maize, and soybean. It was suggested, however, that the balance between positive vs. negative effects is dependent on the soil-plant-inoculant dose system. A. terreus has frequently been described as an important human pathogen. Therefore, its safety manipulation in biotechnological processes for the production of itaconic acid and some drugs and its use in soil-plant systems should be carefully assessed. Some suggestions in this direction are discussed, particularly concerning the uses in crop production.

Itaconic acid production from undetoxified enzymatic hydrolysate of bamboo residues using Aspergillus terreus

Itaconic acid (IA) production by fermentation of undetoxified hydrolysate of bamboo residues by Aspergillus terreus was demonstrated. Monosaccharides were obtained by pretreatment and enzymatic hydrolysis of bamboo residues. A. terreus could not grow and synthesize IA in the hydrolysate. The buffer was confirmed to be an inhibitor, and was successfully replaced by deionized water as the suspension, to release equivalent sugar and eliminate the inhibition. Corn steep liquor significantly improved the adaptability of A. terreus to the hydrolysate at 2.0 g/L. The IA titer obtained (19.35 g/L IA) was the highest to be reported for IA production from lignocellulose without detoxification. Simultaneous saccharification and fermentation and fed-batch fermentation increased the titer to 22.43 g/L and 41.54 g/L, respectively. Meanwhile, economic assessment proved that bamboo residues were potential substrates for IA production with economic effectiveness.

Second-generation itaconic acid: An alternative product for biorefineries?

The ability to produce second-generation itaconic acid by Aspergillus terreus, and the inhibitory effects of hydrolysis by-products on the fermentation were evaluated by cultivation in a synthetic medium containing components usually present in a real hydrolysate broth from lignocellulosic biomasses. The results showed that A. terreus NRRL 1960 can produce itaconic acid and consume xylose completely, but the conversion is less than the fermentation using only glucose. In addition, compared to fermentation of glucose, or even xylose, the mix of both sugars resulted in a lower itaconic acid yield. In the inhibitory test, the final itaconic acid titer was reduced by acetic acid, furfural, and 5-hydroxymethylfurfural concentrations of, respectively, 188, 175, and 700 mg L^-1. However, the presence of any amount of acetic acid proved to be detrimental to itaconic acid production. This research sheds some light on doubts about the biorefinery implementation of itaconic acid production.

Production of Itaconic Acid from Cellulose Pulp: Feedstock Feasibility and Process Strategies for an Efficient Microbial Performance

This study assessed the feasibility of using bleached cellulose pulp from Eucalyptus wood as a feedstock for the production of itaconic acid by fermentation. Additionally, different process strategies were tested with the aim of selecting suitable conditions for an efficient production of itaconic acid by the fungus Aspergillus terreus. The feasibility of using cellulose pulp was demonstrated through assays that revealed the preference of the strain in using glucose as carbon source instead of xylose, mannose, sucrose or glycerol. Additionally, the cellulose pulp was easily digested by enzymes without requiring a previous step of pretreatment, producing a glucose-rich hydrolysate with a very low level of inhibitor compounds, suitable for use as a fermentation medium. Fermentation assays revealed that the technique used for sterilization of the hydrolysate (membrane filtration or autoclaving) had an important effect in its composition, especially on the nitrogen content, consequently affecting the fermentation performance. The carbon-to-nitrogen ratio (C:N ratio), initial glucose concentration and oxygen availability, were also important variables affecting the performance of the strain to produce itaconic acid from cellulose pulp hydrolysate. By selecting appropriate process conditions (sterilization by membrane filtration, medium supplementation with 3 g/L (NH4)2SO4, 60 g/L of initial glucose concentration, and oxygen availability of 7.33 (volume of air/volume of medium)), the production of itaconic acid was maximized resulting in a yield of 0.62 g/g glucose consumed, and productivity of 0.52 g/L·h.

A Review of the Biotechnological Production of Methacrylic Acid

Industrial biotechnology can lead to new routes and potentially to more sustainable production of numerous chemicals. We review the potential of biobased routes from sugars to the large volume commodity, methacrylic acid, involving fermentation based bioprocesses. We cover the key progress over the past decade on direct and indirect fermentation based routes to methacrylic acid including both academic as well as patent literature. Finally, we take a critical look at the potential of biobased routes to methacrylic acid in comparison with both incumbent as well as newer greener petrochemical based processes.

Ustilago Rabenhorstiana—An Alternative Natural Itaconic Acid Producer

Itaconic acid is an industrial produced chemical by the sensitive filamentous fungus Aspergillus terreus and can replace petrochemical-based monomers for polymer industry. To produce itaconic acid with alternative renewable substrates, such as lignocellulosic based hydrolysates, a robust microorganism is needed due to varying compositions and impurities. Itaconic acid producing basidiomycetous yeasts of the family Ustilaginaceae provide this required characteristic and the species Ustilago rabenhorstiana was examined in this study. By an optimization of media components, process parameters, and a fed-batch mode with glucose the final titer increased from maximum 33.3 g·L−1 in shake flasks to 50.3 g·L−1 in a bioreactor. Moreover, itaconic acid was produced from different sugar monomers based on renewable feedstocks by U. rabenhorstiana and the robustness against weak acids as sugar degradation products was confirmed. Based on these findings, U. rabenhorstiana has a high potential as alternative natural itaconic acid producer besides the well-known U. maydis and A. terreus.

Efficient itaconic acid production by Aspergillus terreus: Overcoming the strong inhibitory effect of manganese

Itaconic acid (IA), a building block platform chemical, is produced industrially by Aspergillus terreus utilizing glucose. Lignocellulosic biomass can serve as a low cost source of sugars for IA production. However, the fungus could not produce IA from dilute acid pretreated and enzymatically saccharified wheat straw hydrolyzate even at 100-fold dilution. Furfural, hydroxymethyl furfural and acetic acid were inhibitory, as is typical, but Mn²⁺ was particularly problematic for IA production. It was present in the hydrolyzate at a level that was 230 times over the inhibitory limit (50 ppb). Recently, it was found that PO₄ ^3- limitation decreased the inhibitory effect of Mn²⁺ on IA production. In the present study, a novel medium was developed for production of IA by varying PO₄ ^3- , Fe³⁺ and Cu²⁺ concentrations using response surface methodology, which alleviated the strong inhibitory effect of Mn²⁺ . The new medium contained 0.08 g KH₂ PO₄ , 3 g NH₄ NO₃ , 1 g MgSO₄ ·7H₂ O, 5 g CaCl₂ ·2 H₂ O, 0.83 mg FeCl₃ ·6H₂ O, 8 mg ZnSO₄ ·7H₂ O, and 45 mg CuSO₄ ·5H₂ O per liter. The fungus was able to produce IA very well in the presence of Mn²⁺ up to 100 ppm in the medium. This medium will be extremely useful for IA production in the presence of Mn²⁺ . This is the first report on the development of Mn²⁺ tolerant medium for IA production by A. terreus.

Improved itaconic acid production by Aspergillus niveus using blended algal biomass hydrolysate and glycerol as substrates

Superfluous algal biomass hydrolysate and purified glycerol obtained from biodiesel production were utilized for the production of itaconic acid by Aspergillus niveus. The lipid extracted Gracilaria edulis algal biomass residual was subjected to a pretreatment for the enhanced production of itaconic acid. Glycerol acquired from biodiesel production was pretreated and utilized as a substrate for itaconic acid production. The effect of individual and combined substrate concentration on itaconic acid production was investigated. Ultrasonication combined with the acid pretreated algal biomass produces higher itaconic acid due to the higher level of the total carbohydrate content (58.47 ± 2.57% w/v). After 168 h of incubation, A. niveus utilizes algal biomass hydrolysate and purified glycerol as substrate and produced 31.55 ± 1.25 g/L of itaconic acid and the dry cell weight is 18.24 ± 0.23 g/L respectively. Glycerol and algal biomass hydrolysate was a potential substrate for itaconic acid production by fungal species.

Biomass-Derived Production of Itaconic Acid as a Building Block in Specialty Polymers

Biomass, the only source of renewable organic carbon on Earth, offers an efficient substrate for bio-based organic acid production as an alternative to the leading petrochemical industry based on non-renewable resources. Itaconic acid (IA) is one of the most important organic acids that can be obtained from lignocellulose biomass. IA, a 5-C dicarboxylic acid, is a promising platform chemical with extensive applications; therefore, it is included in the top 12 building block chemicals by the US Department of Energy. Biotechnologically, IA production can take place through fermentation with fungi like Aspergillus terreus and Ustilago maydis strains or with metabolically engineered bacteria like Escherichia coli and Corynebacterium glutamicum. Bio-based IA represents a feasible substitute for petrochemically produced acrylic acid, paints, varnishes, biodegradable polymers, and other different organic compounds. IA and its derivatives, due to their trifunctional structure, support the synthesis of a wide range of innovative polymers through crosslinking, with applications in special hydrogels for water decontamination, targeted drug delivery (especially in cancer treatment), smart nanohydrogels in food applications, coatings, and elastomers. The present review summarizes the latest research regarding major IA production pathways, metabolic engineering procedures, and the synthesis and applications of novel polymeric materials.

Factors Affecting Production of Itaconic Acid from Mixed Sugars by Aspergillus terreus

Itaconic acid (IA; a building block platform chemical) is currently produced industrially from glucose by fermentation with Aspergillus terreus. In order to expand the use of IA, its production cost must be lowered. Lignocellulosic biomass has the potential to serve as low-cost source of sugars for IA production. It was found that the fungus cannot produce IA from dilute acid pretreated and enzymatically saccharified wheat straw hydrolysate even at 100-fold dilution. The effects of typical compounds (acetic acid, furfural, HMF and Mn²⁺, enzymes, CaSO₄), culture conditions (initial pH, temperature, aeration), and medium components (KH₂PO₄, NH₄NO₃, CaCl₂·2H₂O, FeCl₃·6H₂O) on growth and IA production by A. terreus NRRL 1972 using mixed sugar substrate containing glucose, xylose, and arabinose (4:3:1, 80 g L^-1) mimicking the wheat straw hydrolysate were investigated. Acetic acid, furfural, Mn²⁺, and enzymes were strong inhibitors to both growth and IA production from mixed sugars. Optimum culture conditions (pH 3.1, 33 °C, 200 rpm) and medium components (0.8 g KH₂PO₄, 3 g NH₄NO₃, 2.0 g CaCl₂·2H₂O, 0.83-3.33 mg FeCl₃·6H₂O per L) as well as tolerable levels of inhibitors (0.4 g acetic acid, < 0.1 g furfural, 100 mg HMF, < 5.0 ppb Mn²⁺, 24 mg CaSO₄ per L) for mixed sugar utilization were established. The results will be highly useful for developing a bioprocess technology for IA production from lignocellulosic feedstocks.