Tetraselmis suecica F&M-M33 growth is influenced by its associated bacteria.

Natascia Biondi,Carlo Viti,Giulia Cheloni,Luciana Giovannetti,Mario R Tredici,Liliana Rodolfi

doi:10.1111/1751-7915.12865

Natascia Biondi, Carlo Viti + Show 4 more

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https://doi.org/10.1111/1751-7915.12865

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Journal: Microbial Biotechnology	Publication Date: Nov 3, 2017
Citations: 16	License type: CC BY 4.0

Affiliation: University of Florence

Abstract

SummaryAlgal cultures are usually co‐cultures of algae and bacteria, especially when considering outdoor mass cultivation. The influence of associated bacteria on algal culture performance has been poorly investigated, although bacteria may strongly affect biomass (or derived product) yield and quality. In this work, the influence on growth and productivity of Tetraselmis suecica F&M‐M33 of bacterial communities and single bacterial isolates from the algal phycosphere was investigated. Xenic laboratory and outdoor cultures were compared with an axenic culture in batch. The presence of the bacterial community significantly promoted culture growth. Single bacterial isolates previously found to be strictly associated with T. suecica F&M‐M33 also increased growth compared with the axenic culture, whereas loosely associated and common seawater bacteria induced variable growth responses, from positive to detrimental. The increased growth was mainly evidenced as increased algal biomass production and cell size, and occurred after exhaustion of nutrients. This finding is of interest for biofuel production from microalgae, often attained through nutrient starvation processes leading to oil or carbohydrate accumulation. As axenic T. suecica F&M‐M33 showed a similar growth with or without vitamins, the most probable mechanism behind bacterial positive influence on algal growth seems nutrient recycling.

Highlights

Microalgal biotechnology, in recent years, has sparked great interest, initially focused on the potential use of microalgal biomass as feedstock for biofuel production and as a source of alternative foods and food ingredients (Vanthoor-Koopmans et al, 2013)
Xenic laboratory and outdoor cultures were compared with an axenic culture in batch
Single bacterial isolates previously found to be strictly associated with T. suecica F&M-M33 increased growth compared with the axenic culture, whereas loosely associated and common seawater bacteria induced variable growth responses, from positive to detrimental

Summary

Introduction

Microalgal biotechnology, in recent years, has sparked great interest, initially focused on the potential use of microalgal biomass as feedstock for biofuel production and as a source of alternative foods and food ingredients (Vanthoor-Koopmans et al, 2013). For algae to become real players in the market of biofuels and food commodities, production of huge amounts of biomass at low cost is necessary To achieve this goal, besides lowering the operational and capital costs of algal biomass production at large scale (Tredici et al, 2015, 2016), improvement of culture productivity is required. It has been observed that often under phosphorus limitation bacteria compete with algae for this nutrient-depressing algal growth, while under nitrogen limitation the effect of bacteria on algal growth may be neutral or positive, due to a balance between nitrogen release through organic matter degradation and nitrogen immobilization, while in a medium with no nutrient limitation bacteria may stimulate algal growth by providing CO2 (Brussard and Riegmann, 1998; Danger et al, 2007; Amin et al, 2012; Ramanan et al, 2016) This different behaviour may play a 2017 The Authors.

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