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Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The acidic lipase from Rasamsonia emersonii named LIPR has great potential for biodiesel synthesis due to its strong methanol tolerance. Nonetheless, the limited thermostability of LIPR and low expression level in Escherichia coli remain major obstacles to its use in biodiesel synthesis. To enhance the thermostability, the mutant LIPR harboring mutations A126C-P238C for the formation of a new disulfide bond and amino acid substitution D214L was obtained through rational design. To our delight, the thermostability of LIPR mutant was greatly improved. Moreover, a comprehensive optimization strategy, such as employing the Mss signal peptide, co-expressing the molecular chaperone protein disulfide isomerase (PDI), knocking out the vacuolar sorting receptor gene VPS10-01, and overexpressing the dihydroxyacetone synthase gene DAS2, was adopted to obtain the combination-optimized mutant Pichia pastoris strain GS54. Furthermore, the biodiesel synthetic capability with the mutant GS54-LIPR was verified and the production yield was 52.2 % after 24 h in a shake flask. Subsequently, a continuous flow system was adopted to increase the biodiesel yield to 73.6 % within 3 h, demonstrating its efficacy in enhancing enzyme biocatalysis. The engineered GS54-LIPR mutant lipase is an efficient and reusable biocatalyst for the sustained production of biodiesel in a continuous flow reaction., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Copyright of Chinese Journal of Bioprocess Engineering is the property of Chinese Journal of Bioprocess Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background The biosynthesis of high value-added compounds using metabolically engineered strains has received wide attention in recent years. Myo-inositol (inositol), an important compound in the pharmaceutics, cosmetics and food industries, is usually produced from phytate via a harsh set of chemical reactions. Recombinant Escherichia coli strains have been constructed by metabolic engineering strategies to produce inositol, but with a low yield. The proper distribution of carbon flux between cell growth and inositol production is a major challenge for constructing an efficient inositol-synthesis pathway in bacteria. Construction of metabolically engineered E. coli strains with high stoichiometric yield of inositol is desirable. Results In the present study, we designed an inositol-synthesis pathway from glucose with a theoretical stoichiometric yield of 1 mol inositol/mol glucose. Recombinant E. coli strains with high stoichiometric yield (> 0.7 mol inositol/mol glucose) were obtained. Inositol was successfully biosynthesized after introducing two crucial enzymes: inositol-3-phosphate synthase (IPS) from Trypanosoma brucei, and inositol monophosphatase (IMP) from E. coli. Based on starting strains E. coli BW25113 (wild-type) and SG104 (ΔptsG::glk, ΔgalR::zglf, ΔpoxB::acs), a series of engineered strains for inositol production was constructed by deleting the key genes pgi, pfkA and pykF. Plasmid-based expression systems for IPS and IMP were optimized, and expression of the gene zwf was regulated to enhance the stoichiometric yield of inositol. The highest stoichiometric yield (0.96 mol inositol/mol glucose) was achieved from recombinant strain R15 (SG104, Δpgi, Δpgm, and RBSL5-zwf). Strain R04 (SG104 and Δpgi) reached high-density in a 1-L fermenter when using glucose and glycerol as a mixed carbon source. In scaled-up fed-batch bioconversion in situ using strain R04, 0.82 mol inositol/mol glucose was produced within 23 h, corresponding to a titer of 106.3 g/L (590.5 mM) inositol. Conclusions The biosynthesis of inositol from glucose in recombinant E. coli was optimized by metabolic engineering strategies. The metabolically engineered E. coli strains represent a promising method for future inositol production. This study provides an essential reference to obtain a suitable distribution of carbon flux between glycolysis and inositol synthesis.

Insulin detemir is one of the long-acting insulin used in the clinical treatment of diabetes.There are some common problems in the expression of the insulin precursor detemir DesB30, such as low expression and high cost.In this study,soluble insulin precursor detemir was expressed by Pichia pastoris, and the aim of this study was to improve the expression of DesB30 by optimizing fermentation conditions. The expression of the insulin precursor detemir DesB30 was optimized in small scale fermentation by high density fermentation. A 5-L glass fermentation tank was used for the fermentation experiment, and four factors including pH, temperature, concentration of pre-induction bacteria and acceleration of methanol feed were selected for the single-factor experiment to investigate the optimal fermentation conditions of DesB30. The optimal fermentation conditions of DesB30 were pH 6. 0-6. 5, induction temperature 26 V, concentration of pre-induction bacteria 200 g/L,and final flow acceleration of methanol 16. 3 mL/(h-L). Under the optimal fermentation conditions, the expression of DesB30 was up to about 2. 5 g/L. Our findings provide an experimental basis for subsequent large-scale industrial production. [ABSTRACT FROM AUTHOR]

Background: The biosynthesis of high value-added compounds using metabolically engineered strains has received wide attention in recent years. Myo-inositol (inositol), an important compound in the pharmaceutics, cosmetics and food industries, is usually produced from phytate via a harsh set of chemical reactions. Recombinant Escherichia coli strains have been constructed by metabolic engineering strategies to produce inositol, but with a low yield. The proper distribution of carbon flux between cell growth and inositol production is a major challenge for constructing an efficient inositol-synthesis pathway in bacteria. Construction of metabolically engineered E. coli strains with high stoichiometric yield of inositol is desirable. Results: In the present study, we designed an inositol-synthesis pathway from glucose with a theoretical stoichiometric yield of 1 mol inositol/mol glucose. Recombinant E. coli strains with high stoichiometric yield (> 0.7 mol inositol/mol glucose) were obtained. Inositol was successfully biosynthesized after introducing two crucial enzymes: inositol-3-phosphate synthase (IPS) from Trypanosoma brucei, and inositol monophosphatase (IMP) from E. coli. Based on starting strains E. coli BW25113 (wild-type) and SG104 (ΔptsG::glk, ΔgalR::zglf, ΔpoxB::acs), a series of engineered strains for inositol production was constructed by deleting the key genes pgi, pfkA and pykF. Plasmid-based expression systems for IPS and IMP were optimized, and expression of the gene zwf was regulated to enhance the stoichiometric yield of inositol. The highest stoichiometric yield (0.96 mol inositol/mol glucose) was achieved from recombinant strain R15 (SG104, Δpgi, Δpgm, and RBSL5-zwf). Strain R04 (SG104 and Δpgi) reached high-density in a 1-L fermenter when using glucose and glycerol as a mixed carbon source. In scaled-up fed-batch bioconversion in situ using strain R04, 0.82 mol inositol/mol glucose was produced within 23 h, corresponding to a titer of 106.3 g/L (590.5 mM) inositol. Conclusions: The biosynthesis of inositol from glucose in recombinant E. coli was optimized by metabolic engineering strategies. The metabolically engineered E. coli strains represent a promising method for future inositol production. This study provides an essential reference to obtain a suitable distribution of carbon flux between glycolysis and inositol synthesis. [ABSTRACT FROM AUTHOR]

L-amino acid oxidase (AAO) was reported to be capable of converting L-glutamic acid to α-aketoglutaric acid (α-KG). The sequence of AAO from Kitasatospora cheerisanensis was synthesized based on Pichia pastoris codon-usage preferences. AAO gene was cloned into plasmid pPICZα which was transformed into P. pastoris. Next, multi-copy expression plasmids were constructed by using plasmid pHBM905BDM. High-density fermentation was performed and the recombinant enzyme was characterized. The conversion conditions were optimized. By using Escherichia coli expression system, no soluble or active AAO was obtained from two strains after fermentation and induction. We can't obtain high-level expression of recombinant strains by using plasmid pPICZα. Therefore, we constructed multi-copy expression plasmids using plasmid pHBM905BDM. By using this plasmid, multi-copy strains were constructed and named as PAAO1, PAAO2, PAAO3, PAAO4, and PAAO5, respectively. The following results showed that expression of AAO in multicopy strains increased as designed and strain PAAO5 was chosen for high-density fermentation and enzyme activity experiments. After high-density fermentation, we achieved an AAO-expression yield of 120.8 U/mL. After temperature and pH optimization, the highest AAO activity was observed at a temperature and pH of 20°C and 6, respectively. After optimization of the conversion conditions, the average production rate of L-glutamic acid to α-KG was 3.46 g/L/h and the highest α-KG titer (103 g/L) was converted from 120 g/L L-glutamic acid. In this study, AAO was abundantly expressed by using P. pastoris expression system. The following experiments indicated that AAO is suitable for use in industrial applications. [ABSTRACT FROM AUTHOR]

Background: Owing to the growing interest in biofuels, the concept of a biorefinery where biomass is converted to a variety of useful products is gaining ground. We here present how distillery waste is combined with a by-product from a sugar production, molasses, to form a medium for the growth of Lactobacillus plantarum with yields and biomass densities comparable with conventional industrial media. Such approach enables a cost-effective utilization of the problematic wastewater from ethanol and a by-product from sugar production. It is the first approach that attempts to find low-cost media for the production of Lactobacillus plantarum biomass. Results: This study suggests that sieved wheat stillage enriched by adding 1.77 g/l yeast extract and 10% molasses (v/v), with NH4OH used for pH adjustment, may be used as a media for large-scale cultivation of L. plantarum. Such composition of the medium permits a high density of lactic acid 10 bacteria (1.6 x 1010 cfu/ml) to be achieved. Conclusions: The use of a fermentation medium consisting of distillery wastewater and molasses to obtain value-added products (such as LAB biomass and lactic acid) is a possible step for classical ethanol production to move towards a biorefinery model production in which all by and waste products are utilized to increase produced values and reduce waste production. This enables a cost-effective utilization of the problematic wastewater from ethanol and sugar production. [ABSTRACT FROM AUTHOR]

Abstract: Resilin is an elastic protein with outstanding material properties: high resilience and a very high fatigue lifetime. We are interested in the production of resilin-like proteins which can be photo-chemically cross-linked to form rubbery biomaterials to be used in a variety of industrial and medicinal applications. A method has been developed for producing soluble recombinant proteins in small scale fermentation equipment using glycerol batch for initial growth and primary induction by IPTG at carbon source depletion, followed by new growth in lactose-induced culture. Recombinant rec1-resilin [1] has been over-expressed in the host strain Escherichia coli BL21(DE3)pLysS at a level of up to 300mg/l, a greater than 20-fold increase in volumetric productivity, relative to that obtained from conventional IPTG induction in LB medium. The primary induction step before lactose induction in fresh medium resulted in a 2.5- to 3-fold increase of both volumetric productivity and cell specific yield compared to that without primary induction under the same conditions. This method is amenable and suitable for large scale production of soluble resilin-like proteins at a low operating cost. In addition, a simple ‘salt precipitation and heat purification’ method allowed rapid and efficient downstream processing of a large quantity of soluble recombinant resilin-like proteins. These methods will enable investigation of the structural and functional properties of resilin-like proteins, and the development of highly resilient biomaterials. [Copyright &y& Elsevier]

Polyhydroxyalkanoates (PHAs) are polymers obtained by esterification of hydroxy fatty acid monomers. Due to similar mechanical characteristics of traditional petroleum-based plastics, 100% biodegradability and biocompatibility, PHAs are considered to be one of the most potential green materials. However, the application and promotion of PHAs as a green and environmentally friendly material are difficult because of the high production costs. This article focuses on the current methods to reduce production cost of PHAs effectively, such as cell morphology regulation, metabolic pathway construction, economic carbon source utilization and open fermentation technology development. Despite most research results are still limited in laboratory, the research methods and directions provide theoretical guidance for the industrial production of economic PHAs.