Table 5.

Summary of pre-treatment conditions for each species of seaweed, including achieved ethanol yields following fermentation and the maximal total glucose (kg) and total ethanol yields (kg) that could be attained from processing 1 metric tonne (1000 kg) of seaweed from using the optimised pre-treatment parameters

Seaweed species	Pre-treatment at 121 °C	Enzyme hydrolysis solids loading (w/v) (%)a	Achieved ethanol yields (g L−1)b	Total glucose (kg)c	Total ethanol (kg)d
L. digitata	0.75 M H2SO4, 24 min at 25% (w/v) solids loading	2	3.2	40.0	20.4
D. carnosa	H2O, 30 min at 15% (w/v) solids loading	8	5.4	30.2	15.4
U. lactuca	H2O, 24 min at 10% (w/v) solids loading	8	7.8	35.9	18.3

^aNovozymes Cellic® CTec2 dose was not optimised in this work and as such was dosed in an excess (50 FPU/g cellulose) in order to achieve maximum glucose liberation from each seaweed

^bAfter fermentation using S. cerevisiae NCYC2592 at 30 °C

^cGlucose content calculated from levels quantified in the enzyme hydrolysate (hydrolysate quantity liberated from 1 tonne of seaweed)

^dTheoretically achievable pure ethanol concentrations from 1 tonne of seaweed calculated using the liberated glucose quantity (after enzyme hydrolysis) × 0.51