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► Pseudomonas chlororaphis was investigated for production of mcl-PHA latex under controlled conditions on bioreactor scale ► A surplus material, namely saturated biodiesel fraction ...from animal waste lipids, was used as the sole carbon source ► A detailed kinetic analysis of the bioprocess is provided ► Productivity of the mcl-PHA latex is competitive to other mcl-PHA producing organisms on expensive carbon sources.
A novel description of mcl-PHA biosynthesis by Ps. chlororaphis from tallow-based biodiesel as an inexpensive carbon feed stock is presented. Fermentation protocols, kinetic analysis, an efficient product recovery strategy, and product characterization are included. Maximum specific growth rates (μmax.) of 0.08 h−1, 0.10 h−1 and 0.13 h−1, respectively, were achieved in three different fermentation set-ups. Volumetric productivity for mcl-PHA amounted to 0.071g/L h, 0.094g/L h and 0.138g/L h, final intracellular PHA contents calculated from the sum of active biomass and PHA from 22.1 to 29.4wt.-%, respectively. GC-FID analysis showed that the obtained biopolyester predominantly consists of 3-hydroxyoctanoate and 3-hydroxydecanoate, and, to a minor extent, 3-hydroxydodecanoate, 3-hydroxynonanoate, 3-hydroxyhexanoate, and 3-hydroxyheptanoate monomers. The overall distribution of the monomers remained similar, regardless to working volumes, biodiesel concentrations and pre-treatment of the inoculum.
► Valuable mathematical models for PHA production by Cupriavidus necator on combined substrates. ► PHA production on waste substrates from biodiesel (FAME and glycerol). ► New low structured model ...for fed-batch fermentation on glucose with glycerol. ► New low structured model for fed-batch fermentation on FAME with valeric acid. ► In silico optimized feeding of C-sources and PHB/PHBV content by mathematical models.
Two low structured mathematical models for fed-batch production of polyhydroxybutyrate and polyhydroxybutyrate-co-hydroxyvalerate by Cupriavidus necator DSM 545 on renewable substrates (glycerol and fatty acid methyl esters-FAME) combined with glucose and valeric acid, were established. The models were used for development/optimization of feeding strategies of carbon and nitrogen sources concerning PHA content and polymer/copolymer composition. Glycerol/glucose fermentation featured a max. specific growth rate of 0.171h−1, a max. specific production rate of 0.038h−1 and a PHB content of 64.5%, whereas the FAME/valeric acid fermentation resulted in a max. specific growth rate of 0.046h−1, a max. specific production rate of 0.07h−1 and 63.6% PHBV content with 4.3% of 3-hydroxyvalerate (3HV) in PHBV. A strong inhibition of glycerol consumption by glucose was confirmed (inhibition constant ki,G=4.28×10−4gL−1). Applied concentration of FAME (10–12gL−1) positively influenced on PHBV synthesis. HV/PHBV ratio depends on applied VA concentration.
The industrial implementation of cost- and eco-efficient production of bio-based polymeric materials such as polyhydroxyalkanoates (PHAs) or polylactic acid (PLA) requires the comprehension of all ...process steps. The article at hand provides an insight into recent advances in allocation, pretreatment and utilization of raw materials available for biopolymer production in different areas of the world. Further, the high potential and risks of applying continuous process conduction in comparison with batch and fed-batch fermentation mode are elucidated. It is shown that the process design for continuous PHA production strongly depends on the kinetic characteristics for growth and product formation of the applied production strain. In addition, the triggering of the biopolymer properties by fine-tuning of the polyester composition during biosynthesis is demonstrated. Here, the impact of certain process parameters like the partial oxygen tension on the intracellular metabolic fluxes and the supplementation of cosubstrates on the polyester composition are discussed. In addition, such specialists among microbes are presented that possess the metabolic prerequisites to accumulate high-quality copolyesters merely from cheap unrelated carbon sources without the necessity for supplying expensive cosubstrates. In the field of downstream processing, sustainable methods for product isolation during biopolymer production that do not have a negative influence on the environment are presented. Key words: biopolymers, downstream processing, fermentation strategy, polyhydroxyalkanoates, process design, raw materials, white biotechnology
•PHB production by Cupriavidus necator DSM 545 on glycerol.•Developed mathematical model well predicts real cultivation of C. necator on glycerol.•Glycerol-substrate inhibition proposed by Yanno was ...upgraded on double substrate kinetic.•Inoculum concentration is the most influential factor regarding PHB productivity.•Carefully chosen C/N ratio prevents biomass death but does not antagonize PHB synthesis.
Glycerol was utilized by Cupriavidus necator DSM 545 for production of poly-3-hydroxybutyrate (PHB) in fed-batch fermentation. Maximal specific growth rates (0.12 and 0.3h−1) and maximal specific non-growth PHB production rate (0.16gg−1h−1) were determined from two experiments (inocula from exponential and stationary phase). Saturation constants for nitrogen (0.107 and 0.016gL−1), glycerol (0.05gL−1), non-growth related PHB synthesis (0.011gL−1) and nitrogen/PHB related inhibition constant (0.405gL−1), were estimated. Five relations for specific growth rate were tested using mathematical models. In silico performed optimization procedures (varied glycerol/nitrogen ratio and feeding) has resulted in a PHB content of 70.9%, shorter cultivation time (23h) and better PHB yield (0.347gg−1). Initial concentration of biomass 16.8gL−1 and glycerol concentration in broth between 3 and 5gL−1 were decisive factors for increasing of productivity.
mcl-PHA biosynthesis by Pseudomonas citronellolis from tallow-based biodiesel as inexpensive carbon feed stock was accomplished. Fermentation protocols, kinetic analysis, an efficient product ...recovery strategy, and a detailed product characterization are presented.
A maximum specific growth rate, μmax. of 0.10 and 0.08h−1, respectively, was achieved in two different fermentation set-ups. Volumetric productivity for mcl-PHA amounted to 0.036g/Lh and 0.050g/Lh, final intracellular PHA contents calculated from the sum of active biomass and PHA to 20.1 and 26.6wt.%, respectively. GC-FID analysis showed that the obtained biopolyester predominantly consists of 3-hydroxyoctanoate and 3-hydroxydecanoate, and, to a minor extent, 3-hydroxydodecanoate, 3-hydroxynonanoate, 3-hydroxyhexanoate, and 3-hydroxyheptanoate monomers. This was confirmed by 1H- and 13C NMR, also evidencing the occurrence of low quantities of unsaturated and 3-hydroxyvalerate building blocks. High purity of the recovered materials was proofed by elemental analysis. Regarding the results from thermogravimetric analysis, differential scanning calorimetry and molecular mass determination, results were in a range typical for this type of PHA (1st fermentation: decomposition temperature Td=296°C, peak of melting range Tm=48.6°C; glass transition temperature Tg=−46.9°C, degree of crystallinity Xc=12.3%, Mw=66,000, Mn=35,000, dispersity index Pi=1.9; 2nd fermentation: Td=295°C, Tm=53.6°C, Tg=-43.5°C, Xc=10.4%, Mw=78,000, Mn=196,000, Pi=2.5).
Industrijska proizvodnja isplativih i ekoloških biopolimernih materijala, poput polihidroksialkanoata ili polimliječne kiseline, zahtijeva razumijevanje svih faza procesa. Stoga su u radu navedeni ...najnoviji postupci alokacije i prethodne obrade, te načini uporabe sirovina za proizvodnju polimera u različitim dijelovima svijeta. Zatim su procijenjeni mogućnost i rizik primjene kontinuiranog procesa proizvodnje, u usporedbi sa šaržnom fermentacijom s pritokom supstrata ili bez njega. Pokazalo se da dizajn procesa kontinuirane proizvodnje polihidroksialkanoata uvelike ovisi o kinetici rasta proizvodnoga soja i formiranju produkta. Osim toga, preciznim se podešavanjem sastava poliestera potiče oblikovanje različitih biopolimera. Utvrđeno je da djelomična zasićenost kisikom utječe na intracelularne tokove a dodatak kosupstrata na sastav poliestera. U radu su navedene neke vrste mikroorganizama koje bez dodatka skupih kosupstrata mogu akumulirati visokokvalitetne kopoliestere iz jeftinih izvora ugljika. Također su prikazane održive metode izolacije biopolimera koje nemaju negativan utjecaj na okoliš.
The application of biotechnological processes for industrial production can be regarded as promising for sustainable development, although for a range of products, biotechnological production ...strategies have not yet passed the test of economic viability. This is often caused by the cost of the raw materials. Here, a viable solution strategy is identified by the utilization of a broad range of waste and surplus materials that can be upgraded to the role of feedstocks for the biomediated production of desired end products such as polyhydroxyalkanoate biopolymers. The selection of the appropriate waste stream as a feedstock for biotechnological purposes mainly depends on the global region where the production plant will be constructed. To save costs for transportation, facilities for the production of biopolymers, biofuels and biochemicals should be integrated into existing production lines, where the feedstocks directly accrue as waste streams. In Europe and North America, surplus whey from the dairy industry is available in large quantities, whereas huge amounts of non-wood lignocellulosic materials from rice, corn and sugar cane plants are found in many different countries worldwide. The enormously increasing production of biofuels provides a range of by-products such as glycerol and low-quality fatty acid esters from biodiesel production or distillery residues from bioethanol factories. The utilization of waste streams for production of value-added products not only enhances the economics of such products, but also provides industry with a strategy to overcome disposal problems.
OBJECTIVE: To investigate diabetes-specific autoantibodies and additional autoimmune phenomena in a large cohort of young patients with type 1 diabetes. RESEARCH DESIGN AND METHODS: Data from 28,671 ...patients <30 years with type 1 diabetes from 242 specialized centers in Germany and Austria were analyzed. RESULTS: At least one β-cell antibody was present in 81.6% of patients. β-cell-Ab-negative patients were significantly younger at diabetes onset (P < 0.0001). A total of 19.6% had positive thyroid antibodies with female predominance (62%, P < 0.0001). Antibodies to tissue transglutaminase were present in 10.7%, with a significantly longer duration of diabetes (P < 0.0001). Parietal cell antibodies were found in 283 patients, associated with older age (P < 0.001), and adrenal antibodies were present in 94 patients. In 575 patients, at least three different autoimmune phenomena were present. CONCLUSIONS: Thyroid autoimmunity and antibodies suggestive for celiac disease are the most prevalent additional immune phenomena in type 1 diabetes. Parietal/adrenal antibodies are rare.
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