Electron Microscopy and Raman Spectroscopy Characterization of Nanoparticle Coated Diatom Biosilica

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009</jats:p

Plantlet regeneration of Kappaphycus alvarezii var. adik-adik by tissue culture

Three color morphotypes of Kappaphycus alvarezii var. adik-adik (brown, green and red) collected from a farming area in Tictauan Is., Zamboanga City, Philippines were used as explants in the study in order to micropropagate ‘new’ plants. Individual sections of sterile Kappaphycus alvarezii var. adik-adik, initially cultured in a 48-well culture plate containing ESS/2 + E3 + PGR, released callus cells after 4–5&nbsp;days of incubation at 23–25°C, 13:11H LD cycle and 10–15&nbsp;μmol photons m−2 s−1 light intensity. True calli were formed after 29–35&nbsp;days following dense formation of filaments or undifferentiated round cells at the medullary and inner cortical layers of the section. Plantlets (2–3&nbsp;mm long) of Kappaphycus alvarezii var. adik-adik were able to regenerate after 98, 150 and 177&nbsp;days in-vitro among the reds, greens, and browns, respectively. This study established successful methods for the production and regeneration of tissue explants of Kappaphycus alvarezii var. adik-adik which can possibly be used to mass produce ‘new’ cultivars for land- and sea-based nurseries as sources for commercial farming

A novel closed system bubble column photobioreactor for detailed characterisation of micro- and macroalgal growth

Growth of the marine microalga Tetraselmis striata Butcher and the macroalga Chondrus crispus Stackhouse was investigated in batch cultures in a closed system bubble column photobioreactor. A laboratory cultivation system was constructed that allowed online monitoring of pH and dissolved oxygen tension and was used for characterization of photoautotrophic growth. Carbon dioxide addition regulated pH and was used to optimise irradiance. Oxygen was removed from the system by addition of hydrogen over a palladium catalyst to quantify oxygen production. In addition, the bubble column photobioreactor was suited for cultivation of algae due to fast gas-to-liquid mass transfer (k(L)a) and fast mixing provided by split and dual sparging. Specific growth rates (SGRs) were measured using both offline and online measurements. The latter was possible, because rectilinear correlation was observed between carbon dioxide addition and optical density, which shows that carbon dioxide addition may be used as an indirect measurement of microalgal biomass (x). The slope of the rectilinear fit of ln (dx/dt) as a function of the time (t) then revealed the SGR. These determinations revealed detailed information about changes in growth with up to three different SGRs in the different batch cultures of both micro- and macroalgae. The maximum SGRs found by online determination were 0.13 h(-1) for T. striata and 0.12 day(-1) for C. crispus. We have developed and described a system and presented some data handling tools that provide new information about growth kinetics of algae

Optimization of culture conditions for tissue culture production of young plantlets of carrageenophyte Kappaphycus

To improve the production of Kappaphycus plantlets in tissue culture, optimum media concentrations of an Ascophyllum nodosum extract (Acadian Marine Plant Extract Powder, AMPEP), plant growth regulators (PGR), pH–temperature combinations, and explant density were determined. Kappaphycus alvarezii var. tambalang purple (PUR), kapilaran brown (KAP), vanguard brown (VAN), adik-adik (AA), tungawan green (TGR), and K. striatum var. sacol green (GS) were used as explants. Based on the shortest period for shoot emergence and the economical use of AMPEP, the optimum enriched media was 3.0 mg L−1 AMPEP and 0.1 mg L−1 AMPEP + PGR 1 mg L−1 each phenylacetic acid (PAA) and zeatin for PUR, 1.0 mg L−1 AMPEP + PGR for KAP and GS, 0.1 mg L−1 AMPEP + PGR for VAN, and 3.0 mg L−1 AMPEP and 0.001 mg L−1 AMPEP + PGR for AA and TGR. Results showed that the addition of PGR to low concentrations of AMPEP hastened shoot formation. pH–temperature combinations for the most rapid shoot formation were determined for the brown (KAP) and purple (PUR) color morphotypes of K. alvarezii var. tambalang and the green morphotype of K. striatum var. sacol (GS) cultured in 1.0 mg L−1 AMPEP + PGR. The brown morphotype produced the most number of shoots at pH 7.7 at 20°C after as little as 20 days. Purple K. alvarezii showed an increased shoot formation at pH 6.7 at 25°C and the green K. striatum morphotype at pH 8.7 at 25°C. The optimum number of explants added to the culture media was also determined for tungawan green (TGR), brown (KAP), and tambalang purple (PUR) varieties of K. alvarezii in 1.0 mg L−1 AMPEP + PGR. The number of explants and the volume of the culture media combination were also tested. The highest average number of shoots formed occurred in two explants:1 mL culture media (2:1) for KAP and PUR (35.00% and 16.67%, respectively) and 1 explant: 2 mL culture media for the TGR (100.00%) with a range of 0.5–3.0 mm shoot length after 40 days in culture. The earliest shoot formation was observed after 21 days for the brown and 9 days for both the green and purple color morphotypes of Kappaphycus, in all densities investigated. This indicated that within the range tested, the density of explants did not have a significant effect on the rate of shoot formation but did influence the average number generated from the culture. The rate of production of new and improved Kappaphycus explants for a commercial nursery stock was improved through the use of AMPEP with optimized culture media pH, temperature, and density conditions