Premium
The impact of elevated CO 2 concentration on the quality of algal starch as a potential biofuel feedstock
Author(s) -
Tanadul Ornuma,
VanderGheynst Jean S.,
Beckles Diane M.,
Powell Ann L.T.,
Labavitch John M.
Publication year - 2014
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.25203
Subject(s) - starch , chlorella sorokiniana , amylopectin , biofuel , hydrolysis , food science , chemistry , raw material , biomass (ecology) , polysaccharide , botany , algae , biochemistry , chlorella , amylose , agronomy , microbiology and biotechnology , biology , organic chemistry
ABSTRACT Cultured microalgae are viewed as important producers of lipids and polysaccharides, both of which are precursor molecules for the production of biofuels. This study addressed the impact of elevated carbon dioxide (CO 2 ) on Chlorella sorokiniana production of starch and on several properties of the starch produced. The production of C. sorokiniana biomass, lipid and starch were enhanced when cultures were supplied with 2% CO 2 . Starch granules from algae grown in ambient air and 2% CO 2 were analyzed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The granules from algae grown in 2% CO 2 were disk‐shaped and contained mainly stromal starch; granules from cultures grown in ambient air were cup‐shaped with primarily pyrenoid starch. The granules from cells grown in 2% CO 2 had a higher proportion of the accumulated starch as the highly branched, amylopectin glucan than did granules from cells grown in air. The rate of hydrolysis of starch from 2% CO 2 ‐grown cells was 1.25 times greater than that from air‐grown cells and 2–11 times higher than the rates of hydrolysis of starches from cereal grains. These data indicate that culturing C. sorokiniana in elevated CO 2 not only increases biomass yield but also improves the structure and composition of starch granules for use in biofuel generation. These modifications in culture conditions increase the hydrolysis efficiency of the starch hydrolysis, thus providing potentially important gains for biofuel production. Biotechnol. Bioeng. 2014;111: 1323–1331. © 2014 Wiley Periodicals, Inc.