Expression of Trichoderma reesei exo-cellobiohydrolase I in transgenic tobacco leaves and calli

Expression of Trichoderma reesei exo-cellobiohydrolase I (CBHI) gene in transgenic tobacco was under the control of CaMV 35S promoter. In transgenic leaf tissues, CBHI activity up to 66.1 μmol/h/g total protein was observed. In transgenic calli, the highest CBHI activity was 83.6 μmol h/g total protein. Protein immunoblot analysis confirms the presence of CBHI enzyme in both transgenic calli and leaf tissues. CBHI expression levels accounted for about 0.11% and 0.082% of total protein in transgenic leaf tissues and calli, respectively, Furthermore, expression of CBHI gene did not affect normal growth and development of transgenic plants.     

Fingerprinting Trichoderma reesei hydrolases in a commercial cellulase preparation

Polysaccharide degrading enzymes from commercial T. reesei broth have been subjected to “fingerprint” analysis by high-resolution 2-D gelelectrophoresis. Forty-five spots from 11×25 cm Pharmacia gels have been analyzed by LC-MS/MS and the resulting peptide sequences were compared toexisting databases. Understanding the roles and relationships of component enzymes from the T. reesei cellulase system acting on complex substrates is key to the development of efficient artificial cellulase systems for the conversion of lignocellulosic biomass to sugars. These studies suggest follow-on work comparing induced and noninduced T. reesei cells at the proteome level, which may elucidate substrate-specific gene regulation and response.     

核苷酸锆固定化脂肪酶的制备及其催化性能

开发了以核苷酸锆纳米颗粒为载体固定化脂肪酶的方法,考察了固定化时间、缓冲液pH值及浓度和酶载量等因素对固定化酶在有机相中催化烯丙醇酮酯交换反应性能的影响.结果表明,一元尿苷酸锆(粒径30～50nm)是较佳的载体,在磷酸缓冲液pH=8.0和浓度为0.03mol/L时,酶与载体质量比为4,固定化6h制得的固定化酶效果最佳....     

产氢细菌的分离鉴定和条件

从啤酒厂活性污泥中筛选获得一株Bacillussp.以模拟有机废水为底物进行该菌株产氢条件的研究。结果表明,适宜产氢温度为29℃,适宜初始pH值为7,适宜菌体浓度为OD610=0.3,适宜含氧量小于0.63%。在上述所有的适宜条件下,该菌株最大产氢速率达到75.3mmol·d-1·g-1Pro。     

Complete mineralization of methylparathion by Pseudomonas sp. A3

Organophosphorus insecticides are widely used in agriculture. Despite their biodegradable nature, some are highly toxic and their residues are found in the environment. Reports on the mineralization of a spectrum of these insecticides by a single potential strain are scarce. We have isolated a soil isolate, Pseudomonas sp. A3, through enrichment technique, able to degrade methylparathion (MP), malathion, monocrotophos, and Diazinon. The potential of this strain to mineralize MP as a carbon and/or phosphorus source has been evaluated. On hydrolysis of MP, the aromatic portion (p-nitrophenol) was used as a carbon and energy source whereas the alkyl moiety (dithiomethylphosphorothioate) was broken down for the phosphorus source. The results from the experiments involving [U-¹⁴C]p-nitrophenol provided the evidence for incorporation of carbon into the cellular constituents and release of CO₂ from this insecticide. During the breakdown of MP, nitrite was released as a catabolic by-product.     

Biosynthesis of Silver Nanoparticles by Septoria apii and Trichoderma koningii

Silver nanoparticles were synthesized by Septoria apii and Trichoderma koningii for the first time and characterized systematically.     

Structure and Function of a Multidomain Alkaline Xylanase from Alkaliphilic Bacillus Sp. Strain 41M-1

Xylanase is an enzyme that catalyzes the hydrolysis of xylan, a -1,4-linked xylose polymer. Alkaliphilic Bacillus sp. strain 41M-1 secretes a xylanase (xylanase J) that has an alkaline pH optimum. Xylanase J is a multidomain enzyme and consists of two functional domains: a family 11/G catalytic domain and a non-catalytic xylan-binding domain. The xylan-binding domain bound to xylan and enhanced catalytic activity of the adjacent catalytic domain. Mutational analyses revealed some amino acid residues that contribute to catalytic activity, alkaliphily and xylan-binding activity of xylanase J.     

Submerged culture screening of two strains ofStreptomyces sp. with high keratinolytic activity

Keratinases can be used for the production of potentially important hydrolyzed proteins and chemicals. This study investigated the keratinolytic activity ofStreptomyces sp on keratinaceous materials like wool. High levels of proteolytic and keratinolytic activity were obtained after 96 h of culture when two Streptomyces sp strains were grown on basal medium containing mineral salts and 3% (w/v) of defatted wool as a source of energy, carbon, and nitrogen. The cell-free culture filtrates exhibited rapid proteolytic digestion of keratin powder. Currently, the authors are testing whether the enzymatic activity obtained is in fact keratinolytic, and not only an alkaline protease activity.     

Cellulase production by Trichoderma reesei using sawdust hydrolysate

Sawdust hydrolysates were investigated for their ability to support cell growth and cellulase production, and for potential inhibition of Trichoderma reesei Rut C30. Simultaneous fermentations were conducted to compare the hydrolysate-based media with the controls having equivalent concentrations of glucose and Avicel cellulose. Six hydrolysates differing in the boiling durations in the hydrolysis procedure were evaluated. The hydrolysates were found to support cell growth and induce active cellulase synthesis. The maximum specific cellulase production rate was 0.046 filter paper units (FPU)/(g of cells · h) in the hydrolysate-based systems, much higher than that (0.017 FPU/[g of cells · h]) in the controls.     

Isolation of naturally occurring dactylomelane metabolites as Laurencia constituents

Dactylomelol 1, initially isolated from molluscs of the genus Aplysia, was the first example of a monocarbocyclic diterpene skeleton with a C-6-C-11 cyclisation. This paper reports on the identification and structural elucidation of six new diterpenes, compounds 4-9, isolated from specimens of Laurencia sp., together with dactylomelol, all with this particular carbon backbone that we named dactylomelane. This result is the first to confirm a red alga as the biogenetic origin of this class of compounds.