Synergistic effect of co-culture of microalga and actinomycete in diluted chicken manure digestate for lipid production

Microalgae have high potential as organisms that can be used for biodiesel production because they can accumulate high amounts of lipids in a similar manner to oleaginous plants. However, the economic feasibility of their lipid production is still in question. Possible methods of improving that feasibility involve a reduction in cultivation costs using effluents along with an increase in lipid production by co-cultivation with plant growth-supporting microorganisms. Previous studies have found that actinomycetes possess a potential as plant growth-promoters. Thus, this research study is aimed at investigating the effects of the co-cultivation of actinomycetes with microalgae on growth and lipid production in diluted chicken manure digestate. In this study, over 190 actinomycetes were screened for their ability to grow in the digestate, as well as for their plant growth promoting abilities. The actinomycete, Nocardia bhagyanarayanae I-27, could promote chlorophyll alpha, biomass and lipid contents in a co-culture with green microalga Tetradesmus obliquus AARL G022 in 25% diluted digestate. Microalgal major fatty acid methyl esters are a suitable substrate for biodiesel production. In addition, the essential Omega 3 fatty acids, including a-linolenic acid and eicosapentaenoic acid, also increased in volume. Thus, the co-cultivation of plant growth promoting actinomycetes with microalgae in wastewater could be an alternative strategy used to increase biomass and lipid production.