Biostimulant Potential of Scenedesmus obliquus Grown in Brewery Wastewater

Abstract

Microalgae are microorganisms with the capacity to contribute to the sustainable and healthy food production, in addition to wastewater treatment. The subject of this work was to determine the potential of Scenedesmus obliquus microalga grown in brewery wastewater to act as a plant biostimulant. The germination index of watercress seeds, as well as the auxin-like activity in mung bean and cucumber, and in the cytokinin-like activity in cucumber bioassays were used to evaluate the biostimulant potential. Several biomass processes were studied, such as centrifugation, ultrasonication and enzymatic hydrolysis, as well as the final concentration of microalgal extracts to determine their influence in the biostimulant activity of the Scenedesmus biomass. The results showed an increase of 40% on the germination index when using the biomass at 0.1 g/L, without any pre-treatment. For auxin-like activity, the best results (up to 60% with respect to control) were obtained at 0.5 g/L of biomass extract, after a combination of cell disruption, enzymatic hydrolysis and centrifugation. For cytokinin-like activity, the best results (up to 187.5% with respect to control) were achieved without cell disruption, after enzymatic hydrolysis and centrifugation at a biomass extract concentration of 2 g/L.

Analysis of the lipid extraction performance in a cascade process for Scenedesmus almeriensis biorefinery

“…Nonetheless, the fact that only little amount of carbohydrates were detected, does not render the water fraction necessarily without value. The biostimulant activity of the supernatant after PEF-treatment could be evaluated in a similar study like Navarro-López et al [63].…”

Plant Biostimulants from Cyanobacteria: An Emerging Strategy to Improve Yields and Sustainability in Agriculture

“…According to our market survey, the treatment cost can vary, depending on application doses and number of applications, between € 20 and € 375 per hectare ( Table 2 ), the upper part of the range possibly being not affordable for some farmers. To make biostimulants from cyanobacteria more competitive it will be necessary to reduce biomass production costs, for instance by integrating the cultivation with wastewaters treatment (removal of N and P), by using CO 2 from waste streams or by using thermotolerant strains that require no cooling [ 170 , 173 , 174 ]. Besides, to improve the environmental sustainability of the whole process, the production of cyanobacteria can be integrated with the use of renewable energy sources (e.g., photovoltaic and geothermal) [ 167 , 175 ].…”

Strain-Specific Biostimulant Effects of Chlorella and Chlamydomonas Green Microalgae on Medicago truncatula

“…Although most studies on legumes focus on their interaction with plant-growth-promoting rhizobacteria (PGPR), a few studies evaluate the effect of seaweed and MA biostimulants on these plants including Phaseolus vulgaris [7,30], Vigna radiata [6,31,32], Glycine max [33,34] and Medicago sativa [35][36][37]. In plant biostimulant studies, MA were administered to plants in the form of extracts [32,[38][39][40], dry biomass [41][42][43][44][45], spent medium/supernatant [46,47], whole cultures [46] as well as cell suspensions [47,48], and desirable results were achieved. Application of the same MA strain's dry biomass, liquid fertilizer and foliar application all led to positive results, although foliar application had greater effects [49].…”

“…In most studies on the effect of MA on plants, Chlorella [42,[47][48][49][55][56][57][58][59], Scenedesmus [32,34,39] and the cyanobacterium Arthrospira (Spirulina) [60][61][62] species have been investigated for their potential biostimulatory effect on a whole range of plants including corn, spinach, Chinese chives, onions, lettuce and tomatoes. Chlorella is the most popular because of its rapid growth and ability to thrive in a wide range of environmental conditions including adverse ones such as drought, saline, cold and hot habitats.…”