Mixotrophy in green microalgae grown on an organic and nutrient rich waste

Author(s)

Candido, Camila ^[1] ; Lombardi, Ana Teresa ^[2]

Affiliation

^[1] Univ Fed Sao Carlos UFSCar, Programa Posgrad Ecol & Recursos Nat PPGERN, Lab Biotecnol Algas, Rod Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos UFSCar, Dept Bot, Lab Biotecnol Algas, Rod Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY; v. 36, n. 2 JAN 18 2020.
• Web of Science Citations: 0

Abstract

Vinasse is a waste from the alcohol industry that can support microalgal growth because of its mineral and organic contents. Growing microalgae on waste can be a means of its remediation and decrease culture costs. The physiological knowledge of microalgae on waste can generate subsidies to increase biomass productivity. However, few studies have explored the photosynthetic metabolism of microalgae on complex matrices such as vinasse. In the present research, we investigated some physiological aspects related to photosynthesis and growth of several microalgae in centrifuged and diluted vinasse. The species investigated were Chlamydomonas sp., Chlorella sorokiniana, Chlorella vulgaris, Desmodesmus spinosus, Haematococcus pluvialis, Monoraphidium sp., Scenedesmus quadricauda and Tetraselmis gracilis. Daily cell density, in vivo chlorophyll a and final cellular biovolumes (96 h) were monitored to infer about population growth. Maximum and operational photosynthetic yields (phi(M) and phi `(M)), photochemical (qP) and non-photochemical (NPQ) quenchings, light saturation curves and related parameters (alpha, rETR(m) and E-K), as well as theoretical carbon fixation were evaluated using pulse amplitude modulated fluorometry (PAM). The results showed that chlorophyll a, photochemical (qP) and non-photochemical (NPQ) quenchings were not affected in vinasse, but photosynthetic yields, light curves parameters and autotrophic carbon fixation decreased. Connecting these results to the increase in productivities in vinasse lead us to the rationale that mixotrophic metabolism was supporting microalgae growth on the waste. This study offers important insights into the understanding of microalgal photosynthetic physiology on complex organic wastes, generating subsidies for optimization of biotechnological use of vinasse related to microalgae production. (AU)

• FAPESP's process: 18/07988-5 - Bioprospecting, characterization and optimization of Brazilian microalgal strains for CO2 biofixation and bioproducts of commercial importance
• Grantee: Ana Teresa Lombardi
• Support Opportunities: Research Projects - Thematic Grants