Lactic acid fermentation of industrial residues from the macroalga Gelidium corneum towards the improvement of protein content and nutritional value

November 22, 2021

The extraction of agar-agar, from red seaweed species, only uses 15 – 30 % of total biomass, producing high volumes of seaweed residues. In view of a circular economy, the development of value-added applications that can reuse these residues is of great interest. Within this work, industrial residues from the macroalga Gelidium corneum were submitted to a two-step process with the aim of creating a ingredient with improved protein content and nutritional value to be used in aquafeeds. Characterisation of residues revealed contents in fibres and proteins of 35 % dry weight (DW) and 16 – 26 % DW. These residues were submitted to heat pre-treatment followed by enzymatic hydrolysis, with the aim of releasing glucose. Later, hydrolysates were submitted to lactic acid fermentation in shake flasks and in a stirred tank reactor. The best fermentation using shake flasks decreased fibres content to 12 % DW and raised proteins to 19 – 29 % DW. The obtained product was rich in lactic acid, which accounted for 25 % DW. The fed-batch fermentation in the reactor created a product with contents in fibres and proteins around 11 % DW and 18 - 26 % DW. Due to oxygen presence during fermentation, this product was also rich in acetic acid, which accounted for 16 % DW. The best fermentation led to an increase in protein bioaccessibility from 7 % to 23 %. These results show the potential of using lactic acid fermentation to transform seaweed residues and improve its nutritional value.

Authors in the community:

• 

  M

  Matilde Ferreira Narciso

  ist197177

Supervisors of this institution:

• 

  M

  Marília Clemente Velez Mateus

  ist12931

• 

  M

  Maria Teresa Ferreira Cesário Smolders

  ist129469

industrial-biotechnology - Industrial Biotechnology

eng - English

Instituto Superior Técnico