Title:Some Microalgae from the Hawaiian Islands with a Focus on Industrial Applications
VOLUME: 4 ISSUE: 4
Author(s):Adelheid Kuehnle, Robert Schurr and Michael Perez
Affiliation:Kuehnle AgroSystems Inc., Honolulu, HI, USA.
Keywords:Microalgae, 18S rRNA sequence, bioproducts, bioenergy, biorefinery, feed, food, cosmetics, wastewater,
remediation.
Abstract:Background: A small subset of the vast diversity of microalgae present in the Hawaiian Islands was
isolated, cultured, and investigated for potential industrial applications. This subset was composed of
either newly reported isolates of Chlorophytes and Bacillariophytes or several species already well
established in local aquaculture.
Methods: Isolates were identified based on 18S rRNA sequence or morphology where applicable.
Isolates were profiled for constitutive biochemical composition using biomass harvested in late log
phase under nutrient replete conditions.
Results: New isolates examined included Acrochaete, Asterarcys, Chlamydomonas, Chlorella,
Desmodesmus, Marinichlorella, Micractinium, Monoraphidium, Nannochlorum, Parachlorella, Picochlorum,
Podohedriella, Mychonastes, Scenedesmus, Tetraselmis and some diatoms. Several had favorable profiles for potential
use in a fuel and feed biorefinery, for wastewater treatment with CO2 capture, or for more specialized products with
options for cultivation as phototrophs or facultative heterotrophs in freshwater or saltwater. Whole biomass showed a
useful combination of protein and lipids, good in vitro digestibility, and presence of key essential amino acids lysine,
methionine, and cysteine. Many isolates had predominantly C16 to C18 fatty acids while a few had polyunsaturated fatty
acids with options for ω-3, ω-6 and ω-9 combinations. Marinichlorella kaistiae, a new species for Hawai'i, proved
suitable for very large-scale cultivation and conversion into biofuel, and its fatty acid profile varied with cultivation in
freshwater or salt water. Several freshwater diatoms, all of which proved scalable including in saline conditions, may be
new representatives of Humidophila, Sellaphora and Nitzschia. The composition of an exudate produced by Mayamaea, a
taxon previously isolated in Hawai'i in lava tubes, was determined to be a unique mannose-rich exopolysaccharide.
Conclusion: Several Hawai'i-sourced strains described here are already of benefit in biofuels and treatment of effluents
including CO2, and are anticipated to have value in next generation cosmetics and ‘cosmeceuticals’ to impact skin
appearance, health and disease applications. Moreover, with protein having higher intrinsic value than biofuels, it is
informative to characterize algal strains at a stage in biomass production that reflects high protein with constitutive lipid
content.
