Effects of ocean acidification on the growth and biochemical composition of a green alga (Ulva fasciata) and its associated microbiota

Abstract

In marine ecosystems, fluctuations in surface-seawater carbon dioxide (CO 2 ), significantly influence the whole metabolism of marine algae, especially during the early stages of macroalgal development. In this study, the response of the green alga Ulva fasciata for elevating ocean acidification was investigated using four levels of p CO 2 ~ 280, 550, 750 and 1050 µatm. Maximum growth rate (6.6% day −1 ), protein (32.43 %DW) and pigment (2.9 mg/g) accumulation were observed at p CO 2 -550 with an increase of ~2-fold compared to control. On the other hand, lipid and carbohydrate contents recorded their maximum production (4.23 and 46.96 %DW, respectively) at p CO 2 -750 while control showed 3.70 and 42.37 %DW, respectively. SDS-PAGE showed the presence of unique bands in response to p CO 2, especially at 550 µatm. Dominant associated bacteria was shifted from Halomonas hydrothermalis of control to Vibrio toranzoniae at p CO 2 -1050. These findings suggest that ocean acidification at 550 µatm might impose noticeable effects on growth, protein, pigments, and protein profile of U. fasciata, which could be a good source for fish farming. While, p CO 2 -750 was recommended for energetic purpose, due to its high lipid and carbohydrate contents.

Deciphering role of technical bioprocess parameters for bioethanol production using microalgae

“…Characterization of optimized biomass shows high carbon, oxygen and phosphorus accumulation with resulted maximum absorption peaks in spectral region of carbohydrates and lipids. The carbohydrates content (58% (w/w) of CDW) of optimized biomass was found comparably higher than carbohydrates content of strains reported earlier such as Ulva fasciata (46.96%), Chlorella salina (50%) ( Barakat et al, 2021 , Mayers et al, 2018 ) and comparable with the highest carbohydrate content of 49% and 50% reported for commercially important microalgae Chlamydomonas sp . ( Morales-Sánchez et al, 2020 ) and Chlorella vulgaris ( Ferreira et al, 2019 ) respectively.…”

Commercial Seaweed Liquid Extract as Strawberry Biostimulants and Bioethanol Production

“…The Mediterranean Sea is home to around 1124 seaweed species, at least 20% of which are indigenous [ 34 , 35 ] and which are represented throughout the year. However, this area needs to be taken in our consideration, as it faces anthropogenic activity, ocean acidification [ 36 , 37 ], microplastic pollution [ 38 ], etc. According to the previous stress and pollution, these seaweeds accumulate several primary and secondary metabolites that can be used in several applications, such as carbohydrates, making them a good bioethanol source.…”

Application of a novel biological-nanoparticle pretreatment to Oscillatoria acuminata biomass and coculture dark fermentation for improving hydrogen production

“…Protein content was determined according to the Bradford method [ 87 ]. Total carbohydrates were estimated by spectrophotometry using phenol–sulphuric acid against glucose standard [ 88 ] according the procedures of the previous studies [ 81 , 89 ].…”