ABSTRACT
Tetracarbon organic acids are important platform chemicals that are widely used in the food, chemical, medicine, material industries and agriculture. Compared with the traditional petrochemical process, the production of tetracarbon organic acids by microbial fermentation is more promising due to milder reaction conditions, greener process and better environmental compatibility. This review summarizes the biosynthetic pathways and metabolic mechanisms for the production of tetracarbon organic acids, and illustrates recent advances, challenges, and future perspectives in the production of tetracarbon organic acids by naturally selected or purposefully engineered strains.
Subject(s)
Acids , Biosynthetic Pathways , Fermentation , Metabolic Engineering , Organic ChemicalsABSTRACT
Exoelectrogens are promising for a wide variety of potential applications in the areas of environment and energy, which convert chemical energy from organic matter into electrical energy by extracellular electrons transfer (EET). Microorganisms with different mechanisms and EET efficiencies have been elucidated. However, the practical applications of exoelectrogens are limited by their fundamental features. At present, it is difficult to realize the extensive application of exoelectrogens in complex and diverse environments by means of traditional engineering strategies such as rational design and directed evolution. The exoelectrogens with excellent performance in environments can be screened with efficient strain identification technologies, which promote the widespread applications of exoelectrogens. The aims of this review are to summarize the methods of screening based on different types of exoelectrogens, and to outline future research directions of strain screening.
Subject(s)
Bioelectric Energy Sources , Electricity , Electron TransportABSTRACT
Aims: D-tagatose is a natural ketohexose which can be used as a functional sweetener in foods, diary and beverages products. Isolation of new bacterial strains having the ability to produce D-tagatose is a continuously trending topic of research. Study Design: Screening of strains with D-tagatose production by identification and determination of its ability to produce D-tagatose content. Place and Duration of Study: School of Food and Biological Engineering, Jiangsu University between May 2018 and April 2019. Methodology: We initially screened and identified the strains capable of producing D-tagatose through kimchi liquid, and determined the species and genetic characteristics of the strain by physiological, biochemical and molecular biological identification, and then determined the content of D-tagatose by high performance liquid chromatography. Finally calculate the ability of the strain to produce D-tagatose. Results: In this study, 4 strains of lactic acid bacteria (LAB) were isolated from kimchi sample. The isolates were identified as Lactobacillus spp. (Lactobacillus plantarum, Lactobacillus fermentum and Lactobacillus salivarius) on the basis of morphological, physicochemical characteristics and analysis of 16S rDNA gene sequence. Because of the novelty, strain designated as L. salivarius UJS 003 was considered for D-tagatose yield. Fermentation of D-tagatose was carried out using galactose as substrate for 48 hr at 37 °C, and HPLC method was used to determine the yield. The experimental results exhibited a D-tagatose yield of 3.134 g/L by L. salivarius UJS 003. Conclusion: The strain UJS 003 represented as a potent D-tagatose producer and could be useful in a variety of biotechnological and industrial processes, particularly food and beverage industries.
ABSTRACT
Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulosc Congo red coltnre medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively.
ABSTRACT
Strains from the cellulose-containing environment were collected. Primary screening (by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively.
ABSTRACT
The Gram negative strain H8005 was isolated from alkali silt on the site of paper mill. Under optimum conditions, the alkali cellulase activitig (CMCase) of shaking flask culture of H8005 was 4.2 IU/mL. The optimal conditions for the enzymatic reaction were about 55℃ and pH 8.0. At pH 7.0～9.0, the enzyme showed high activity and good stability. Mn~(2+ ), Fe~(3+) were the activators and Cu~(2+) , Pb~(2+ )were the inhibitors of the enzyme. The novel cellulase produced by H8005 showed great potential in the textile biofinishing and detergent industry.
ABSTRACT
One carboxypeptidase producing strain was obtained from 28 proteinase producing strains, by analyzing the products of peptides hydrolyzed by the enzyme of the strains According to the characteristics of the morpha and the colonies, the screened strain belongs to aspergillus genera The activity of its carboxypeptidase reached maximum at the 84th hour after fermentation
ABSTRACT
The strain of DG7 isolated from the oilwater sample in DAGANG oilfield could produce surfactant ?acids and gas in the culture medium in which the diesel was sole carbon source .The strain was Gram-negative, motive, rod and growed facultatively in the 0 to 18.5% NaCl. Based on its characters, the strain was identified as a member of the genus Aeromonas, but there were some differences between this strain and the described species of this genus in some biochemical features, suggesting that it could be a new species of the genus.