Bulk Carotenoids

One metric used to indicate a physiological response in algal cultures is pigment concentration. Typically the photosynthetic pigment chlorophyll a is used to indicate the health of a growing culture or as a measure of productivity in a population. I am extracting and measuring carotenoid production in Nannochloropsis salina to determine the relationship between culture management and physiological status. 96 well plates make the measurement of numerous samples a breeze. A standard curve can be created with Beta-Carotene. 

 

Bulk carotenoids loaded into 96 well plate

Bulk carotenoids loaded into 96 well plate

Algae Pigments: Carotenoids as Indicators for Stress

One of my main research interests in terms of algae production is how culture management affects algal biomass and bio-compound yield. In response to environmental stress algae algae can change their biochemical composition drastically. For instance changes in light level can cause changes in pigment concentrations; changes in nutrient levels can cause changes in lipid content. These relationships are specific to each species of algae and also respond to environmental conditions in a complex way. 

I am currently looking at carotenoid profiles in N. salina in response to culture management strategies. This data combined with the lipid profiles will help design culture methods that can provide a predictable yield biomass/bio-compounds. 

Pigment extracts of N. salina ready for HPLC.

How do culture conditions change the composition of algae cells?

Part of my research at New Mexico State University involves determining how culture conditions affect the chemical composition of biomass in Nannochloropsis salina. I will be looking at both lipid profile and pigment content in relation to culture conditions (harvest and feeding regimes). This will be important to help determine culture management strategies that will help increase yields in production systems. 

More details to come as data comes in. 

GC samples awaiting analysis. 


Simple Solutions for Increased Algal Productivity

I firmly believe in the K.I.S.S method. Ockham, of Occam's razor surmised that in the absence of certainty, a hypothesis with the fewest assumptions should be chosen. To me, this means that the simplest answer is the most correct. Although it is not easy to find the most elegant answer to a problem we must try. Since large scale production is still in its infancy, I've tried to determine how simplicity relates to yield of algae and algae products.

Often it seems like some people are employed to make things more difficult. Imagine how much time and resources would be saved, how many more projects would succeed if efficiency and efficacy were the rules. You get the idea, no matter which side of the line you stand. 

So, reducing complexity to simplicity is our goal. In terms of algal production the complexity is nature itself. All abiotic and biotic factors converging to influence the productivity and biochemical composition of a single cell. Much valuable work has been done studying how and where all of these data lie. But, we have yet been able to successfully apply this knowledge to meet our own estimates of algae production. 

My contention is that something as simple (yet with complex implications) as harvest and feeding regimes can have positive influences on algal biomass yields and biocompound production rates. If we can alter the culture management to influence our yields, within the range as defined by our system parameters, then we might be one small step closer to a operable production system. 

Now, look at this graph and see if you agree. 

Yield of algal cells in response to harvest volume, nutrient addition and media type. 

The above figure shows total number of Nannochloropsis salina cells yielded from an experiment with 12 treatments over the course of 25 days. The treatments are media, either f/2 or wastewater, added nutrients (+) or normal, and harvest volume (15, 30 or 45%). Letters above the bars indicate similarity (for shared letters) or dissimilarity. With this data set I am able to show that increasing harvest volume always results in increased yield, no matter the media or nutrient levels. This, I think, is simple and useful for anyone wanting to produce algae. That is the simple answer, and I will stop there. There is more to talk about in terms of harvest and feeding timing, and how this all influences bio-compound production. Keep thinking.