Production of Chitosan- and Chitin-like Exopolymers by Acetobacter xylinum ATCC 10245

Lee,Jin W.,Deng,Fang,Yeomans,Walter G.,Allen,Alfred L.,Gross,Richard A.,Kaplan,David L. 한국생명과학회 1998 한국생명과학회 학술발표회 Vol.20 No.-

To biosynthesize modified cellulose, glucose analogs including 3-O-methyl-D-glucose, glucosamine, N-acetylglucosamine, and 2-deoxy-D-glucose were used separately as the carbon source. Incorporation of glucosamine and N-acetylglucosamine repeat units into cellulose by Acetobacter xylinum ATCC 10245 was confirmed by GC, GC/MS, FTIR and ¹H-NMR. Based on data, the average molar percentages of glucosamine and N-acetylglucosamine repeat units into exopolymers were 19% and 18%, respectively. The yields of exopolymers made with glucosamine and N-acetylglucosamine as carbon source after 7 day culture were 0.37 ㎎/㎖ and 0.67 ㎎/㎖ , respectively, whereas that of glucose was 3.9 ㎎/㎖. The yield of exopolymer made with the mixture of glucose (0.5%, v/v) and glucosamine (1.5%, v/v) as carbon sources was 1.75 ㎎/㎖, and the average molar percentage of glucosamine repeat unit into the exopolymer was 17%. Exopolymers made with glucosamine and N-acetylglucosamine were fractionated by 10% acetic acid and DW, respectively, The molar ratio of glucose to glucosamine in the acetic acid (10%, v/v) soluble fractionation of glucosamine incorporated exopolymer was 0.6: 1.0. The molar ratio of glucose to N-acetylglucosanune in the water soluble fraction of N-acetylglucosamine incorporated exopolymer was 0.8 : 1.0.

Biosynthesis of Novel Exopolymers by Aureobasidium pullulans

Lee,Jin W.,Deng,Fang,Yeomans,Walter G.,Allen,Alfred L.,Gross,Richard A.,Kaplan,David L. 한국생명과학회 1998 한국생명과학회 학술발표회 Vol.20 No.-

Exopolymers produced by A. pullulans ATCC 42023 under aerobic conditions with glucose, mannose, and glucose analogs including 3-O- methyl-D-glucose, glucosamine, N-acetylglucosamine, and 2-deoxy-D- glucose as carbon sources contained glucose and mannose. The molar ratio of glucose to mannose in exopolymers and the molecular weight of exopolymers varied with the carbon source and culture time. Exopolymers synthesized with glucose and mannose as carbon sources showed glucose contents of 87±3 and 89±2%, respectively, with a decreased molecular weight from 3.50 - 2.12 x 10^6 to 0.85 - 0.77 x 10^6 with culture time. The molar ratio of glucose to mannose in the exopolymer synthesized with glucosamine changed from 55±3 : 45±3 to 29±2 : 71±2 and its molecular weight increased from 2.73 x 10^6 to 4.86 x10^6 with culture time. The molar ratio of glucose to mannose in exopolymers ranged from 87±3 : 13±3 to 28±2 : 72±2 and can be controlled by carbon source. On the basis on the results from enzyme hydrolysis of the exopolymers and comparison of ¹H- and ^(13)C-NMR chromatograms, the mannose as a monomeric component is substituted for glucose without changing the structure of pullulan.

Exopolymers from curdlan production: Incorporation of glucose-related sugars by Agrobacterium sp. strain ATCC 31749

Lee, Jin W.,Allen, Alfred L.,Deng, Flank,Yeomans, Walter G.,Kaplan, David L.,Gross, Richard A. 東亞大學校附設遺傳工學硏究所 1998 遺傳工學硏究 Vol.- No.5

Three different exopolymers were purified from cultures of Agrobacterium sp. strain ATCC 31749 grown in a mineral salts medium containing 2% glucose at 30℃ for 5 days under aerobic culture conditions. These exopolymers were curdlan (extracellular, homo-B-(1-3)-gulcan.water insoluble at neutral pH), a water-soluble noncurdlan-type exopolymer A (WSNCE-A), and a water-soluble noncurdlan-type exopolymer B (WSNCE-B). Curdlan. WSNCE-A. and WSNCE-B composed by weight 61,27,and 12%,respectively, of the exopolymer produced from goucose. Compositions of all polymers were confirmed by gas chromatography (GC) and gas chromatography -mass spectrometry(GC-MS). The WSNCE-A is composed of glucose and galactose with lower contents of rhamnose. The WSNCE-B consists of glucose and mannose. To biosynthesize modified biopolymers, glucose-related sugars including 3-0-methyl-D-glucose, 2-amino-2-deoxy-D-glucose, and 2-acetamido-2-deoxy-D-glucose(N-acetylgucosamine)were fed separately as the sole carbon source. Using 3-O-methyl-D-glucose, 8-12 mol% of the curdlan repeats were 3-O-methyl-D-glucose based on GC and H-nuclear magnetic resonance spectrometry. N-Acetylgucosamine was incorporated into WSNCE-A at 10 mol% based on the GC-MS but was not found in curdlan or WSNCE-B. Trois exopolymeres differents ont ete purifies a partir de cultures d'Agrobacterium sp. souche ATCC 31749, dont la croissance s'est effectuee a 30℃ durant 5 jours sur un milieu contenant des sels mineraux et 2% de glucose dans des conditions aerobies. Ces trois exopolymeres se sontreveles etre:un type coagule(curdlan) extracellulaire. insoluble dans 1'eau a pH neutre et constitue d'homo-B-(1-3)-glucane, et deux types solubles, non coagules, soit 1'exopolymere A (WSNCE-A) et 1'exopolyere B(WSNCE-B). Les poids respectifs du type coagule esdes deux types noncoagules A et B ont represente 61,27 et 12% de 1'exopolymere produit a partir du glucose. La composition de chacun des polymeres a ete identifiee par chromatographie en phase gazeuse(GC) et par chromatographie en phage gazeuse-spectrometrie de masse (GC-MS). Le WSNCE-A s'est revele constitue de glucose et de galactose avec faible teneur en rhamnose, et lw WSNCE-B, de glucose et de mannose. Dans le but de biosynthetiser des biopolymeres modifies, des sucres apparentes au glucose ont ete incorpores separement aux milieux de culture comme seule source de carbone:le 3-O-methyl-D-glucose, le 2-amino-2-desoxy-D-glucose, et le 2-acetamido-2-desoxy-D-glucose(N-acetylgulcosamine). Utilisant le 3-O-methyl-D-glucose, 8-12 mol% des repetitions du type coagule ont ete du 3-O-methyl-D-glucose, d'apres la GC et la spectrometrie de resonnance magnetique nucleaire-'H. La N-acetylglucosamine a ete incorporee dans le WSNCE-A a 10 mol% d'apres les GC-MS, mails il n'a pas ete trouve chez les exopolymeres coagules ou le WSNCE-B.

Molecular cloning and antifungal activity of an inhibitor cysteine knot peptide from the bumblebee Bombus ignitus

Park, H.G.,Deng, Y.,Lee, K.S.,Kim, B.Y.,Yoon, H.J.,Lee, K.Y.,Jin, B.R. 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol. No.

<P>The honeybee inhibitor cysteine knot (ICK) peptide acts as an antifungal peptide and insecticidal venom toxin. However, the ICK peptide from bumblebees has not been characterized. Here, we report the molecular cloning and antifungal activity of a bumblebee (Bombus ignitus) ICK peptide (BiICK). We identified a BiICK that contains an ICK fold. The BiICK was expressed in the epidermis, fat body, and venom gland of B. ignitus worker bees. A 6.7-kDa recombinant BiICK peptide was expressed in baculovirus-infected insect cells. Recombinant BiICK peptides directly bound to Beauveria bassiana, Ascosphaera apis, and Fusarium graminearum, but they did not bind to Escherichia coli, Paenibacillus larvae, or Bacillus thuringiensis. Consistent with this finding, BiICK exhibited antifungal activity against fungi. These results demonstrate that BiICK acts as an antifungal peptide. (C) 2015 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society. Published by Elsevier B.V. All rights reserved.</P>

Hydraulic fracturing experiments of highly deviated well with oriented perforation technique

Zhu, Hai Y.,Deng, Jin G.,Liu, Shu J.,Wen, Min,Peng, Cheng Y.,Li, Ji R.,Chen, Zi J.,Hu, Lian B.,Lin, Hai,Guang, Dong Techno-Press 2014 Geomechanics & engineering Vol.6 No.2

In order to investigate the effect of different perforation angles (the angle between the perforation direction and the maximum horizontal principal stress) on the fracture initiation and propagation during hydraulic fracturing of highly deviated well in oil & gas saturated formation, laboratory experiments of the hydraulic fracturing had been carried out on the basis of non-dimensional similar criteria by using 400^3 $mm^3$ cement cubes. A plane fracture can be produced when the perforations are placed in the direction of the maximum horizontal principal stress. When the perforation angle is $45^{\circ}$, the fractures firstly initiate from the perforations at the upper side of the wellbore, and then turn to the maximum horizontal principal stress direction. When the well deviation angle and perforation angle are both between $45^{\circ}$ and $90^{\circ}$, the fractures hardly initiate from the perforations at the lower side of the wellbore. Well azimuth (the angle between the wellbore axis and the maximum horizontal principal stress) has a little influence on the fracture geometries; however it mainly increases the fracture roughness, fracture continuity and the number of secondary fractures, and also increases the fracture initiation and propagation pressure. Oriented perforating technology should be applied in highly deviated well to obtain a single plane fracture. If the well deviation angle is smaller, the fractures may link up.

Cementing failure of the casing-cement-rock interfaces during hydraulic fracturing

Hai Y. Zhu,Jin G. Deng,Jun Zhao,Hu Zhao,Hai L. Liu,Teng Wang 사단법인 한국계산역학회 2014 Computers and Concrete, An International Journal Vol.14 No.1

Using the principle of damage mechanics, zero-thickness pore pressure cohesive elements(PPCE) are used to simulate the casing-cement interface (CCI) and cement-rock interface (CRI). The traction-separation law describes the emergence and propagation of the PPCE. Mohr-coulomb criteria determines the elastic and plastic condition of cement sheath and rock. The finite element model (FEM) of delamination fractures emergence and propagation along the casing-cement-rock (CCR) interfaces during hydraulic fracturing is established, and the emergence and propagation of fractures along the wellbore axial and circumferential direction are simulated. Regadless of the perforation angle (the angle between the perforation and the max. horizontal principle stress), mirco-annulus will be produced alonge the wellbore circumferential direction when the cementation strength of the CCI and the CRI is less than the rock tensile strength; the delamination fractures are hard to propagate along the horizontal wellbore axial direction; emergence and propagation of delamination fractures are most likely produced on the shallow formationwhen the in-situ stresses are lower; the failure mode of cement sheath in the deep well is mainly interfaces seperation and body damange caused by cement expansion and contraction, or pressure testing and well shut-in operations.