Biodegradable and Biocompatible Biomaterial, Polyhydroxybutyrate, Produced by an Indigenous Vibrio sp. BM-1 Isolated from Marine Environment

Polyhydroxybutyrate (PHB) is one of the polyhydroxyalkanoates (PHAs) which has biodegradable and biocompatible properties. They are adopted in the biomedical field, in, for example, medical implants and drug delivery carriers. This study seeks to promote the production of PHB by Vibrio sp. BM-1, isolated from a marine environment by improving constituents of medium and implementing an appropriate fermentation strategy. This study successfully developed a glycerol-yeast extract-tryptone (GYT) medium that can facilitate the growth of Vibrio sp. BM-1 and lead to the production of 1.4 g/L PHB at 20 h cultivation. This study also shows that 1.57 g/L PHB concentration and 16% PHB content were achieved, respectively, when Vibrio sp. BM-1 was cultivated with MS-GYT medium (mineral salts-supplemented GYT medium) for 12 h. Both cell dry weight (CDW) and residual CDW remained constant at around 8.2 g/L and 8.0 g/L after the 12 h of cultivation, until the end of the experiment. However, both 16% of PHB content and 1.57 g/L of PHB production decreased rapidly to 3% and 0.25 g/L, respectively from 12 h of cultivation to 40 h of cultivation. The results suggest that the secretion of PHB depolymerase that might be caused by the addition of mineral salts reduced PHB after 12 h of cultivation. However, work will be done to explain the effect of adding mineral salts on the production of PHB by Vibrio sp. BM-1 in the near future

In-situ disinfection and a new downstream processing scheme from algal harvesting to lipid extraction using ozone-rich microbubbles for biofuel production

The scaling up and downstream processing costs of biofuels from microalgae are major concerns. This study focuses on reducing the cost by using energy efficient methods in the production of microalgae biomass and the downstream processes (biomass harvesting and lipid extraction). Ozonation of Dunaliella salina (green alga) and Halomonas (Gram-negative bacterium) mixed cultures for 10 min at 8 mg/L resulted in a reduction in the bacterial contaminant without harming the microalga. Harvesting of D. salina cells through microflotation resulted in a 93.4% recovery efficiency. Ozonation of the harvested microalgal cells for 60 min produced three main saturated hydrocarbon compounds (2-pentadecanone, 6, 10, 14-trimethyl; hexadecanoic acid; octadecanoic acid) consisting of 16 to 18 carbons. By systematically switching the carrier gas from CO2 to O3, the microbubble-driven airlift loop bioreactor (ALB) delivers nutrient to the culture and in-situ disinfection respectively. Further, modulating the bubble size to match particle size ensures recovery of the cells after culture. All three key operations (disinfection, harvesting and lipid extraction) are assembled in a scalable, relatively energy efficient process

Marine Biocatalysts: Enzymatic Features and Applications

In several recent reports related to biocatalysis the enormous pool of biodiversity found in marine ecosystems is considered a profitable natural reservoir for acquiring an inventory of useful biocatalysts. These enzymes are characterized by well-known habitat-related features such as salt tolerance, hyperthermostability, barophilicity and cold adaptivity. In addition, their novel chemical and stereochemical characteristics increase the interest of biocatalysis practitioners both in academia and research industry. In this review, starting from the analysis of these featuring habitat-related properties, important examples of marine enzymes in biocatalysis will be reported. Completion of this report is devoted to the analysis of novel chemical and stereochemical biodiversity offered by marine biocatalysts with particular emphasis on current or potential applications of these enzymes in chemical and pharmaceutical fields. The analysis of literature cited here and the many published patent applications concerning the use of marine enzymes supports the view that these biocatalysts are just waiting to be discovered, reflecting the importance of the marine environment. The potential of this habitat should be thoroughly explored and possibly the way to access useful biocatalysts should avoid destructive large-scale collections of marine biomass for enzyme production. These two aspects are day by day increasing in interest and a future increase in the use of marine enzymes in biocatalysis should be expected

Identification of polyhydroxyalkanoates in Halococcus and other haloarchaeal species

Polyhydroxyalkanoates (PHAs) are accumulated in many prokaryotes. Several members of the Halobacteriaceae produce poly-3-hydroxybutyrate (PHB), but it is not known if this is a general property of the family. We evaluated identification methods for PHAs with 20 haloarchaeal species, three of them isolates from Permian salt. Staining with Sudan Black B, Nile Blue A, or Nile Red was applied to screen for the presence of PHAs. Transmission electron microscopy and 1H-nuclear magnetic resonance spectroscopy were used for visualization of PHB granules and chemical confirmation of PHAs in cell extracts, respectively. We report for the first time the production of PHAs by Halococcus sp. (Halococcus morrhuae DSM 1307T, Halococcus saccharolyticus DSM 5350T, Halococcus salifodinae DSM 8989T, Halococcus dombrowskii DSM 14522T, Halococcus hamelinensis JCM 12892T, Halococcus qingdaonensis JCM 13587T), Halorubrum sp. (Hrr. coriense DSM 10284T, Halorubrum chaoviator DSM 19316T, Hrr. chaoviator strains NaxosII and AUS-1), haloalkaliphiles (Natronobacterium gregoryi NCMB 2189T, Natronococcus occultus DSM 3396T) and Halobacterium noricense DSM 9758T. No PHB was detected in Halobacterium salinarum NRC-1 ATCC 700922, Hbt. salinarum R1 and Haloferax volcanii DSM 3757T. Most species synthesized PHAs when growing in synthetic as well as in complex medium. The polyesters were generally composed of PHB and poly-ß-hydroxybutyrate-co-3-hydroxyvalerate (PHBV). Available genomic data suggest the absence of PHA synthesis in some haloarchaea and in all other Euryarchaeota and Crenarchaeota. Homologies between haloarchaeal and bacterial PHA synthesizing enzymes had indicated to some authors probable horizontal gene transfer, which, considering the data obtained in this study, may have occurred already before Permian times

Alcances y limitaciones del modelo de planificación participativa en Bolivia : conflictos de intereses en los municipios productores de coca

Tesis (Doctor en Estudios Urbanos y Ambientales)--El Colegio de México, Centro de Estudios Demográficos, Urbanos y Ambientales, 201

Chromohalobacter sarecensis sp. nov., a psychrotolerant moderate halophile isolated from the saline Andean region of Bolivia

A moderately halophilic, aerobic, motile, Gram-negative, rod-shaped bacterium (strain LV4T) was isolated from saline soil around the lake Laguna Verde in the Bolivian Andes. The organism is a heterotroph, able to utilize various carbohydrates as a carbon source. It showed tryptophan deaminase, oxidase and catalase activity, but was unable to produce indole or H2S; nitrate was not reduced. The G+C content of the genomic DNA was 56·1 mol%. The pH range for growth was 5–10, temperature range was 0–45 °C and the range of NaCl concentrations was 0–25 % (w/v). On the basis of 16S rRNA gene sequence analysis, strain LV4T was found to be closely related to Chromohalobacter canadensis DSM 6769T and Pseudomonas beijerinckii DSM 7218T; however, its DNA–DNA relatedness with these type strains was low. Strain LV4T resembled other Chromohalobacter species with respect to various physiological, biochemical and nutritional characteristics but also exhibited differences. Thus, a novel species, Chromohalobacter sarecensis sp. nov., is proposed, with LV4T (=CCUG 47987T=ATCC BAA-761T) as the type strain.Fil: Quillaguamán, Jorge. Lund University; Suecia. Universidad Mayor de San Simón; BoliviaFil: Delgado, Osvaldo Daniel. Lund University; Suecia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Mattiasson, Bo. Lund University; SueciaFil: Hatti Kaul, Rajni. Lund University; Sueci