II. A.I.b. Collection and Screening Activities-1983

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National Renewable Energy Laboratory

Collect single species cultures of microalgae from the arid regions of

Colorado, Utah and New Mexico for product and performance screening

Develop media that are suitable for their growth.

Evaluate each species for its temperature and salinity tolerances, and

quantify growth rates and proximate chemical composition for each species

over the range of tolerated conditions.

Each objective was met during the course of research within the ASP. The following pages

describe in detail the major findings of the work conducted by SERI researchers.

II.A.1.b. Collection and Screening Activities-1983

The first collecting trips made by SERI researchers took place in the fall of 1983. Five saline hot

springs in Western Colorado were selected for sampling because of their abundant diatom

populations, and because a variety of water types was represented. Water samples were used to

inoculate natural collection site water that had been enriched with N (ammonium and nitrate) and

phosphate (P) and then filter sterilized. Water samples were also taken for subsequent chemical

analyses. The temperature and conductivity of the site water were determined at the time of

collection. Conductivity ranged from 1.9 mmhos@cm-2 at South Canyon Spring to 85.0

mmhos@cm-2 (nearly three times the conductivity of seawater) at Piceance Spring. Water

temperature at the time of collection ranged from 11° to 461C.

In the laboratory, researchers tried to isolate the dominant diatoms from the enriched water

samples. Cyanobacteria and other contaminants were removed primarily with agar plating.

Approximately 125 unialgal diatom strains were isolated. The predominant genera found were

Achnanthes, Amphora, Caloneis, Camphylodiscus, Cymbella, Entomoneis, Gyrosigma, Melosira,

Navicula, Nitzschia, Pleurosigma, and Surirella.

A standardized lipid analysis protocol was not yet in place to screen these strains. However, many

algal strains were known to accumulate lipids under conditions of nutrient stress. Microscopic

analysis of cells grown under N-deficient conditions revealed lipid droplets in several strains,

particularly in Amphora and Cymbella.

In addition to yielding several promising algal strains, this initial collection trip was useful for

identifying areas for improving the collection and screening protocols. Some of these

improvements were implemented for the 1984-collecting season, and are described in the next

section.

Publications:

Barclay, W.R. (1984) AMicroalgal technology and research at SERI: Species collection and

characterization.@ Aquatic Species Program Review: Proceedings of the April 1984 Principal

Investigator=s Meeting, Solar Energy Research Institute, Golden, Colorado, SERI/CP-231-2341;

pp. 152-159.

A Look Back at the Aquatic Species Program--Technical Review