Enhancement of beta-Glucosidase Activity from a Brown Rot Fungus Fomitopsis pinicola KCTC 6208 by Medium Optimization

beta-Glucosidase, which hydrolyzes cellobiose into two glucoses, plays an important role in the process of saccharification of the lignocellulosic biomass. In this study, we optimized the activity of beta-glucosidase of brown-rot fungus Fomitopsis pinicola KCTC 6208 using the response surface methodology (RSM) with various concentrations of glucose, yeast extract and ascorbic acid, which are the most significant nutrients for activity of beta-glucosidase. The highest activity of beta-glucosidase was achieved 3.02% of glucose, 4.35% of yeast extract, and 7.41% ascorbic acid where ascorbic acid was most effective. The maximum activity of beta-glucosidase predicted by the RSM was 15.34 U/mg, which was similar to the experimental value 14.90 U/mg at the 16th day of incubation. This optimized activity of beta-glucosidase was 23.6 times higher than the preliminary activity value, 0.63 U/mg, and was also much higher than previous values reported in other fungi strains. Therefore, a simplified medium supplemented with a cheap vitamin source, such as ascorbic acid, could be a cost effective mean of increasing beta-glucosidase activity.

Physiological Functionalities of Vitis hybrid (Sheridan)-Rubus coreanus Red Wine Made by Saccharomyces cerevisiae

Vitis hybrid (Sheridan)-Robus coreanus red wine was vinified by fermentation of a mixture of Vitis hybrid and Robus coreanus must at 25degrees C for 10 days. The Vitis hybrid-Robus coreanus red wine had ethanol contents of 10.9%. It had high antihypertensive angiotensin I-converting enzyme (ACE) inhibitory activity of 57.8% and antioxidant activity of 64.8%. Changes in the physicochemical properties and functionality of the Vitis hybrid-Robus coreanus red wine was investigated during a post-fermentation period of three months. The ACE inhibitory activity of the red wine increased as the post-fermentation period prolonged, and showed the highest ACE inhibitory activity of 70.4% 60 days post-fermentation. However, the antioxidant activity declined significantly to 47.2% during the post-fermentation period of 60 days. In terms of sensory evaluation, the Vitis hybrid-Robus coreanus red wine had the best acceptability 60 days post-fermentation.

Gene expression and characterization of 2-keto-3-deoxy-gluconate kinase, a key enzyme in the modified Entner-Doudoroff pathway of Serratia marcescens KCTC 2172

We cloned 2-keto-3-deoxy-gluconate kinase (KDGK), which catalyzes the phosphorylation of 2-keto-3-deoxygluconate (KDG) to 2-keto-3-deoxy-6-phophogluconate (KDPG) from Serratia marcescens KCTC 2172. The nucleotide sequence revealed a single open reading frame containing 1,208 bp and encoding for 309 amino acids, with a molecular weight of 33,993 Da. The enzyme was purified via GST affinity chromatography. The putative KdgT binding site was detected upstream of the initial codon. The KDG kinase utilized 2-ketogluconate (KG) and KDG as substrates. The optimal temperature and pH for KDGK activity were 50ºC and 8.0, respectively.

The Importance and Global Trends of Biological Resources: The Introduction of the KCTC and Fungal Resources / 대한의진균학회지

In 1985, the Korean Collection for Type Cultures (KCTC), a former organization of the Korea Research Institute of Bioscience and Biotechnology Biological Resource Center (KBRC), was officially approved by the Ministry of Science and Technology (MOST) as a gene bank node and became a member of the World Federation for Culture Collections (WFCC). The KBRC was also designated as an International Depository Authority (IDA) under Budapest Treaty in 1990. As a national bio-infra for biological resources, the main functions of the KBRC are 1) collection, preservation and distribution of biological resources, 2) research and development of core technologies for valuable bioresources, and 3) construction of local and international network of biological resources and information. As major activities in 2007, about 1,300 type and reference strains including bacteria, actinomycetes, yeasts, filamentous fungi, anaerobes, cell lines and patent strains were newly acquired and about 4,000 strains were distributed to academia, industries and research institutes. The KBRC published 49 papers regarding biological resources and described 18 new microbial species. Especially, a big progress was made in several aspects: establishment of the back-up depository system for over 3,300 patent strains, development of the barcode system for computerized and centralized management of biological resources, and structural remodeling. The KBRC is going to promote tighter networking among domestic and international culture collections, to strengthen the national depository system for bioproducts from research, and to emphasize research and development related to the collection and preservation of valuable biological resources. Consequently, the KBRC will expand its roles not only as a national infrastructure for life science and biotechnology but also as a fundamental basis of many industries in an era of bio-economy in the 21st century.