Sort by

Found 381 results

Open Access

Review

01 September 2023

In Vitro BioTransformation (ivBT): Definitions, Opportunities, and Challenges

Great needs always motivate the birth and development of new disciplines and tools. Here we propose in vitro BioTransformation (ivBT) as a new biomanufacturing platform, between the two dominant platforms—microbial fermentation and enzymatic biocatalysis. ivBT mediated by in vitro synthetic enzymatic biosystems (ivSEBs) is an emerging biomanufacturing platform for the production of biocommodities (i.e., low-value and bulk biochemicals). ivSEB is the in vitro reconstruction of artificial (non-natural) enzymatic pathways with numerous natural enzymes, artificial enzymes, and/or (biomimetic or natural) coenzymes without living cell’s constraints, such as cell duplication, basic metabolisms, complicated regulation, bioenergetics, and so on. The two great needs (i.e., food security and the carbon-neutral renewable energy system) have motivated the birth and development of ivBT. Food security could be addressed by making artificial food from nonfood lignocellulose and artificial photosynthesis for starch synthesis from CO2. The carbon-neutral renewable energy system could be addressed by the construction of the electricity-hydrogen-carbohydrate cycle, where starch could be a high density of hydrogen carrier (up to 14.8% H2 wt/wt) and an electricity storage compound (greater than 3000 Wh/kg). Also, ivBT can make a number of biocommodities, such as inositol, healthy sweeteners (e.g., D-allulose, D-tagatose, D-mannose), advanced biofuels, polymer precursors, organic acids, and so on. The industrial biomanufacturing of the first several biocommodities (e.g., myo-inositol, D-tagatose, D-mannose, and cellulosic starch) would wipe off any prejudice and doubt on ivBT. Huge potential markets of biocommodities with more than tens of trillions of Chinese Yuan would motivate scientists and engineers to address the remaining technical challenges and develop new tools within the next decade.

Keywords: Biocommodity; Biomanufacturing; In vitro biotransformation; In vitro synthetic enzymatic biosystem; Food security; Carbon-neutral energy system
Synth. Biol. Eng.
2023,
1
(2), 10013; 
Open Access

Review

28 August 2023

Dynamic Metabolic Control: From the Perspective of Regulation Logic

Establishing microbial cell factories has become a sustainable and increasingly promising approach for the synthesis of valuable chemicals. However, introducing heterologous pathways into these cell factories can disrupt the endogenous cellular metabolism, leading to suboptimal production performance. To address this challenge, dynamic pathway regulation has been developed and proven effective in improving microbial biosynthesis. In this review, we summarized typical dynamic regulation strategies based on their control logic. The applicable scenarios for each control logic were highlighted and perspectives for future research direction in this area were discussed.

Keywords: Dynamic regulation; Control logic; Feedback control; Oscillation
Synth. Biol. Eng.
2023,
1
(2), 10012; 
Open Access

Editorial

25 August 2023
Open Access

Review

15 August 2023

Green Composites Using Naturally Occurring Fibers: A Comprehensive Review

Depletion of non-renewable resources and health hazards of petroleum-based polymers and plastics has enforced the development of eco-friendly materials. The use of conventional plastics has to be minimized and can be replaced with environmentally friendly and sustainable bio-based polymers or biopolymers due to extensive environmental impact. A major share of petroleum-based polymers is used for polymeric composites with research focus on green composites and biocomposites containing renewable/bioderived matrix polymer and fillers from naturally occurring fibers. Biocomposites hold great promise to replace petroleum-based polymer composites owing to their lower cost, non-toxicity, abundance of raw material, renewability, and high specific strength. All these merits of biocomposites have led to an increment in the development of new biocomposites with enhanced properties, wide applicability and ever demanding criteria. The recently published review studies detailed the raw materials used, fabrication techniques, characterization, and applications including biodegradation and rheological studies performed in recent years. This review covers all the important properties of biocomposites along with detailed description of synthesis, properties, characterizations and applicability of these green composites in several areas. The review also focuses on their raw materials, types, recent biocomposites, processing techniques, characterizations, applications, and current challenges with future aspects.

Keywords: Biopolymers; Natural fibers; Biocomposites; Biodegradation; Sustainability
Sustain. Polym. Energy
2023,
1
(2), 10010; 
Open Access

Article

15 August 2023

Thermal and Economic Evaluations of a Drain Water Heat Recovery Device under Transient Conditions

This study explores the transient characteristics of a drain water heat recovery (DWHR) device employed for heat recovery from warm grey water in buildings. Experimental measurements were conducted to investigate the response time of the DWHR device under various flow conditions. The thermal performance of the system was assessed using both transient and steady-state effectiveness analyses. The findings reveal that the response time is influenced by the water volume within the system, with an increase observed, and by the water flow rate, which leads to a decrease in response time. Additionally, a decrease in effectiveness is noted when hot water is used in short and frequent intervals. Furthermore, an economic analysis demonstrates that considering the transient behavior of the device results in a significant overall decrease of 37% in annual savings. Specifically, the usage of sinks exhibits a reduction in annual savings by 56%, while showers show a decrease of 13% in annual savings.

Keywords: Drain water heat recovery; Heat exchanger; Experimental investigation; Transient
Clean Energy Sustain.
2023,
1
(1), 10004; 
Open Access

Article

08 August 2023

Where Do Chinese Doublets Come From?—The Doublets from Prehistory to the Era of the Book of Poetry

The earliest writing in China is the oracle bone inscriptions of the Shang Dynasty, which records early Chinese, also known as oracle bone Chinese, which are all monosyllabic-words (1300 BC). In the Bronze Inscriptions of the Western Zhou Dynasty and later handed down documents, doublets appear (beginning in 1046 BC). At present, the philological academy believes that the doublets recorded with two Chinese single-characters come from reduplication of two single-character symbols, but there is no complete argument and reliable evidence. This article, by using the opposite method of argument, reversely assumes that the single-characters (monosyllabic words) come from doublets and tries to demonstrate it. The article proves the truth of the origin of doublets based on the word distribution and semantic correspondence between doublets and single-characters in “the Book of Poetry”, that is, doublets are the source and single-characters are flows. Among them, 39.66% of the doublets have no corresponding single-characters, and they are the characters created to record doublets; 41.92% of the meanings of doublets have nothing to do with the meanings of single-characters, which proves that the doublets does not come from the combination of single-characters; 12.46% of the meanings of doublets are interpreted as the meanings of single-characters, which are the subjective errors of later generations of interpreters; the remaining 5.66% are only associated with proclitics and enclitics rather than single-characters. Finally, the article proposes that doublets originate from a unique mechanism of expressive morphology, which is a new type of etymological theory outside the morphological grammar system, and can create various polysyllabic ideophones, including the onomatopoeia or mimetic words. The article proves that a language begins with the creation of words. In the prehistoric period before the oracle bone inscriptions, Chinese ancestors had invented a large number of distinctive doublets (AA), couplets (AB) and other polysyllabic words (xA, or ABB, ABA’B), or ideophones. Due to the difficulty of writing, the doublets were hidden in spoken language for hundreds of years. It was not until the time of “Book of Poetry” and “Book of History” in the bronze inscriptions of the Western Zhou Dynasty that it entered the history and has continued to this day. Doublets are the earliest Chinese words and the beginning of Chinese civilization.

Keywords: Doublet; Single-character; Classification for character usage; Expressive morphology; Word creation; The Book of Poetry
Di Jiang*  
Nat. Anthropol.
2023,
1
(1), 10005; 
Open Access

Editorial

28 July 2023
Open Access

Review

28 July 2023

Challenging Post-translational Modifications in the Cell-free Protein Synthesis System

Post-translational modifications (PTMs) represent a cornerstone in the complexity of the proteome, significantly contributing to diversifying protein structure and function. PTMs can considerably influence protein function, stability, localization, and interactions with other molecules. Therefore, it is important when choosing a protein expression system to ensure the precise incorporation of PTMs during protein synthesis, which is paramount for producing biologically active proteins. The cell-free protein synthesis (CFPS) system has emerged as a powerful protein synthesis platform and research toolkit in synthetic biology. The open nature of the system allows the reaction environment to be tailored to any protein of interest to promote specific PTMs, thus allowing for the production of a protein with desired modifications. This review presents various PTMs achieved in the CFPS systems, providing insights into current challenges, successes, and future prospects.

Keywords: Cell-free protein synthesis; Post-translational modification; Biomanufacturing; Disulfide bonds; Glycosylation
Synth. Biol. Eng.
2023,
1
(2), 10011; 
Open Access

Article

19 July 2023

Hydroxybenzoic Acid Production Using Metabolically Engineered Corynebacterium glutamicum

Hydroxybenzoic acids (HBAs), including 4-HBA, 3-HBA, and 2-HBA, are valuable platform chemicals for production of commodity materials and fine chemicals. Herein, we employed metabolic engineering techniques to enhance the production of these HBAs in Corynebacterium glutamicum ATCC 13032. Our approach augmented the shikimate pathway and eliminated genes associated with HBA degradation, particularly phenol 2-monooxygenase encoded by cg2966. Increased titers of 3-HBA and 4-HBA were achieved via selection of suitable promoters for 3-hydroxybenzoate synthase and chorismate pyruvate lyase. A tac-M1 promoter was suitable for chorismate pyruvate lyase expression and 8.3 g/L of 4-HBA production was achieved. Efficient production of 2-HBA was enabled by maintaining a balanced expression of isochorismate synthase and isochorismate pyruvate lyase. Consequently, strains KSD5-tacM1-H and KSD5-J2-PE exhibited production levels of 19.2 g/L of 3-HBA and 12.9 g/L of 2-HBA, respectively, using 1 L jar fermenter containing 80 g/L of glucose. Therefore, this engineered strain platform holds significant potential for production of other valuable products derived from chorismate.

Keywords: Corynebacterium glutamicum; Hydroxybenzoic acid; 2-hydroxybenzoic acid; 3-hydroxybenzoic acid; Metabolic engineering; Chorismate derivatives
Open Access

Article

05 July 2023

Photocatalytic Efficiency of Suspended and Immobilized TiO2 P25 for Removing Myclobutanil, Penconazole and Their Commercial Formulations

Fungicide application in viticulture is a major source of surface and groundwater contamination. It is therefore essential to find solutions to stop this environmental pollution. Heterogeneous photocatalysis is an advanced oxidation method for the degradation and mineralization of organic pollutants in water. TiO2 P25 photocatalyst in suspension has been used for removing the fungicides Myclobutanil and Penconazol, and their respective commercial formulations Systhane and Topas, in contaminated water. The apparent kinetic constants kapp of fungicides removal over 30 min batch treatment was higher for a mixture of pure molecules of Myclobutanil and Penconazol than for a mixture of their commercial formulations (17.5 × 10−3 by comparison with 10.3 × 10−3 min−1 for Myclobutanil, and 10.0 × 10−3 by comparison with 2.80 × 10−3 min−1 for Penconazol). TOC removal constants kTOC were similar for the two mixtures, due to the presence of mineral and organic additives in the commercial formulations. To easily recover the photocatalyst after fungicide removal, TiO2 P25 has been supported on β-SiC foam. Fungicides degradation was lower with supported photocatalysts than with the suspension of photocatalyst nanoparticles (NPs) because of a lower concentration of active sites on the supported photocatalyst than in the catalyst suspension. However, catalyst recovery and reuse after fungicide removal is obviously easier with TiO2/β-SiC material than with a suspension of TiO2 which requires long and expensive filtration operations.

Keywords: Fungicides; Photocatalysis; Myclobutanil; Penconazol; TiO2/β-SiC
Photocatal. Res. Potential
2024,
1
(1), 10004; 
TOP