Publications by authors named "Joshua Lowrey"

4 Publications

  • Page 1 of 1

Recycling of lipid-extracted hydrolysate as nitrogen supplementation for production of thraustochytrid biomass.

J Ind Microbiol Biotechnol 2016 08 7;43(8):1105-15. Epub 2016 May 7.

Department of Process Engineering and Applied Science, Faculty of Engineering, Dalhousie University, Halifax, NS, B3H 4R2, Canada.

Efficient resource usage is important for cost-effective microalgae production, where the incorporation of waste streams and recycled water into the process has great potential. This study builds upon emerging research on nutrient recycling in thraustochytrid production, where waste streams are recovered after lipid extraction and recycled into future cultures. This research investigates the nitrogen flux of recycled hydrolysate derived from enzymatic lipid extraction of thraustochytrid biomass. Results indicated the proteinaceous content of the recycled hydrolysate can offset the need to supply fresh nitrogen in a secondary culture, without detrimental impact upon the produced biomass. The treatment employing the recycled hydrolysate with no nitrogen addition accumulated 14.86 g L(-1) of biomass in 141 h with 43.3 % (w/w) lipid content compared to the control which had 9.26 g L(-1) and 46.9 % (w/w), respectively. This improved nutrient efficiency and wastewater recovery represents considerable potential for enhanced resource efficiency of commercial thraustochytrid production.
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http://dx.doi.org/10.1007/s10295-016-1779-xDOI Listing
August 2016

Nutrient recycling of lipid-extracted waste in the production of an oleaginous thraustochytrid.

Appl Microbiol Biotechnol 2016 May 22;100(10):4711-21. Epub 2016 Mar 22.

Department of Process Engineering and Applied Science, Faculty of Engineering, Dalhousie University, Sexton House E102, Halifax, NS, Canada.

Improving the economics of microalgae production for the recovery of microbial oil requires a comprehensive exploration of the measures needed to improve productivity as well as to reduce the overall processing costs. One avenue for cost reduction involves recycling the effluent waste water remaining after lipid extraction. This study investigates the feasibility of recycling those wastes for growing thraustochytrid biomass, a heterotrophic microalgae, where wastes were generated from the enzymatic extraction of the lipids from the cell biomass. It was demonstrated that secondary cultures of the tested thraustochytrid grown in the recycled wastes performed favorably in terms of cell and oil production (20.48 g cells L(-1) and 40.9 % (w/w) lipid) compared to the control (13.63 g cells L(-1) and 56.8 % (w/w) lipid). Further, the significant uptake of solubilized cell material (in the form of amino acids) demonstrated that the recycled waste has the potential for offsetting the need for fresh medium components. These results indicate that the implementation of a nutrient recycling strategy for industrial microalgae production could be possible, with significant added benefits such as conserving water resources, improving production efficiency, and decreasing material inputs.
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http://dx.doi.org/10.1007/s00253-016-7463-2DOI Listing
May 2016

Sequential recycling of enzymatic lipid-extracted hydrolysate in fermentations with a thraustochytrid.

Bioresour Technol 2016 Jun 10;209:333-42. Epub 2016 Mar 10.

Department of Process Engineering and Applied Science, Faculty of Engineering, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.

This study extends the findings of prior studies proposing and validating nutrient recycling for the heterotrophic microalgae, Thraustochytrium sp. (T18), grown in optimized fed-batch conditions. Sequential nutrient recycling of enzymatically-derived hydrolysate in fermentors succeeded at growing the tested thraustochytrid strain, with little evidence of inhibition or detrimental effects upon culture health. The average maximum biomass obtained in the recycled hydrolysate was 63.68±1.46gL(-1) in 90h the first recycle followed by 65.27±1.15gL(-1) in 90h in the subsequent recycle of the same material. These compared to 58.59gL(-1) and 64.92gL(-1) observed in fresh media in the same time. Lipid production was slightly impaired, however, with a maximum total fatty acid content of 62.2±0.30% in the recycled hydrolysate compared to 69.4% in fresh control media.
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http://dx.doi.org/10.1016/j.biortech.2016.03.030DOI Listing
June 2016

Nutrient and media recycling in heterotrophic microalgae cultures.

Appl Microbiol Biotechnol 2016 Feb 16;100(3):1061-1075. Epub 2015 Nov 16.

Department of Process Engineering and Applied Science, Faculty of Engineering, Dalhousie University, Halifax, Nova Scotia, Canada.

In order for microalgae-based processes to reach commercial production for biofuels and high-value products such as omega-3 fatty acids, it is necessary that economic feasibility be demonstrated at the industrial scale. Therefore, process optimization is critical to ensure that the maximum yield can be achieved from the most efficient use of resources. This is particularly true for processes involving heterotrophic microalgae, which have not been studied as extensively as phototrophic microalgae. An area that has received significant conceptual praise, but little experimental validation, is that of nutrient recycling, where the waste materials from prior cultures and post-lipid extraction are reused for secondary fermentations. While the concept is very simple and could result in significant economic and environmental benefits, there are some underlying challenges that must be overcome before adoption of nutrient recycling is viable at commercial scale. Even more, adapting nutrient recycling for optimized heterotrophic cultures presents some added challenges that must be identified and addressed that have been largely unexplored to date. These challenges center on carbon and nitrogen recycling and the implications of using waste materials in conjunction with virgin nutrients for secondary cultures. The aim of this review is to provide a foundation for further understanding of nutrient recycling for microalgae cultivation. As such, we outline the current state of technology and practical challenges associated with nutrient recycling for heterotrophic microalgae on an industrial scale and give recommendations for future work.
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http://dx.doi.org/10.1007/s00253-015-7138-4DOI Listing
February 2016