The terrestrial cyanobacterium Nostoc commune is an anhydrobiotic organism with extreme longevity. Recovery of photosynthesis by rehydration was examined using our laboratory stocks of dry N. commune thalli after long-term storage in a desiccated state. In the samples stored at room temperature for over 8 years, photosynthetic oxygen evolution was barely detectable, whereas oxygen consumption was recovered. There was an exceptional case in which photosynthetic oxygen evolution recovered after 8 years of storage at room temperature. Both photosynthetic oxygen evolution and respiratory oxygen consumption were recovered in dry thalli stored at -20°C for over 15 years. Consistent with the recovery of photosynthetic oxygen evolution, Fv/Fm was detected in the samples stored at -20°C at levels similar to those of freshly collected N. commune colonies. Carotenoids, scytonemin and chlorophyll a appeared to be intact in the dry thalli stored at -20°C, but β-carotene was not detected in the samples stored at room temperature. α-Tocopherol was intact in the samples stored at -20°C but was degraded in the samples stored at room temperature. These results suggest that dry thalli of N. commune are capable of sustaining biological activities for a long time, although they are gradually damaged when stored at room temperature.

Researchers continue to search for efficient processes to reduce the production costs of rare sugars. In this paper, we report a novel D-xylose isomerase from Shinella zoogloeoides NN6 (SzXI) and its application for efficient rare sugar production. Purified SzXI did not show remarkable properties when compared with those of a previously reported D-xylose isomerase. However, NN6 was found to express inducible SzXI and constitutive D-allulose 3-epimerase (SzAE) when cultivated with D-xylose as the sole carbon source. These two enzymes were partially purified and immobilized onto HPA25L, an anion exchange resin. The co-immobilized SzXI and SzAE (i-XA) showed optimal activity at 65°C in sodium phosphate buffer (pH 7.5) and 90°C in sodium phosphate buffer (pH 6.5), respectively. i-XA produced D-ribulose via D-xylulose from D-xylose at a conversion ratio of D-xylose:D-xylulose:D-ribulose of 72:18:10. Furthermore, D-allulose was also produced via D-fructose using D-glucose as the substrate, with a D-allulose yield of 11.2%. This is the first report describing a bacterium expressing D-xylose isomerase and D-allulose 3-epimerase that converts readily available sugars such as D-glucose and D-xylose to rare sugars.

Rice (Oryza sativa L.) straw is an agricultural byproduct of high yield, and its disposal by burning has detrimental effect on ecosystem. It has potential as source of fermentable sugars for industrial use; however, it requires effective pretreatment to remove lignin. Bacterial enzymes based pretreatment is advantageous due to their extracellular nature, and tolerance to higher temperature, pH and oxygen limitation. We herein report screening of lignocellulose degradation environment of vermicompost for ligninolytic bacteria, and studying role of Micrococcus unnanensis strain B4 in delignification of rice straw. The bacterium was capable to degrade acid soluble and insoluble lignin; and produced lignin degrading laccase and peroxidase having maximum activity at pH 6.5 and 72 h incubation. Both enzymes exhibited alkaline pH stability, and thermal stability with retention of 100 % activity on pre-incubation at 60 ℃ for 1 h. The enzymes were used for pretreatment of rice straw using chemicals (acetic acid:hydrogen peroxide) pretreatment as reference. Scanning electron microscopy of pretreated rice straw samples showed alteration in morphology with exposure of cellulosic components. Enzymatically pretreated rice straw on saccharification by a commercial cellulase yielded about 400 mg of reducing sugar per gram, comparable to that released on chemical pretreatment. Hence, pretreatment based on M.unnanensis strain B4 and its ligninolytic enzymes can be an alternative to chemical pretreatment for saccharification of rice straw to fermentable sugars.

In this study, we successfully isolated two compounds, 17T223A (1, C₂₂ H₂₂ O₁₀ ) and 17T223B (2, C₂₂ H₂₀ O₉ ), from a culture of Streptomyces sp. 17T223. Spectroscopic analyses revealed that these two compounds belong to the spiroximicin family. The chemical structure of 2 was consistent with that of the established antibiotic spiroximicin, whereas 1 was previously unknown. Furthermore, 1 exhibited moderate radical -scavenging activity, with an ED ₅₀ of 1000 μM, whereas 2 showed no radical -scavenging activity, even at an ED₅₀ of 2000 μM. Significant antimicrobial activity was exhibited by 2 whereas 1 exhibited no antimicrobial activity, suggesting that the epoxide portion of 2 influences its antimicrobial activity.

A new antifungal polyketide, named hakuhybotric acid (1), was isolated from a cultured broth of a mycoparasitic fungus Hypomyces pseudocorticiicola FKI-9008, together with two known analogs, F2928-1 (2) and Cladobotric acid E (3). Their structures were elucidated by MS and NMR analyses. Hakuhybotric acid was a new analog of Cladobotric acid where two epoxy groups in F2928-1 were replaced with olefins. All compounds showed antifungal activity against four different species of Aspergillus spp., the causative agents of aspergillosis. It was suggested that mycoparasitic fungi are a useful source to search antifungal drug lead compounds.

The marine bacterium Cobetia sp. IU180733JP01 (5-11-6-3) can accumulate poly(3- hydroxybutyrate) [P(3HB)] during cultivation on alginate or waste Laminaria sp. Here, we examined this strain’s ability to utilize various carbon sources for P(3HB) production. When cultured in mineral salt medium containing 1% (w/v) glucose, fructose, glycerol, or gluconic acid, the strain showed better growth and higher P(3HB) production than on alginate, with fructose enabling the highest P(3HB) yield (0.8 ± 0.06 g/L). We also predicted metabolic pathways for P(3HB) synthesis based on draft genome sequence analysis, in which carbon sources are assimilated through Entner–Doudoroff and Embden–Meyerhof pathways, and the resultant acetyl-CoA is converted into P(3HB). Our findings reveal the potential of the 5-11-6-3 strain for application in bioplastic production from not only marine biomass but also other biomass and industrial wastes.