Hydrolysis pretreatment of algae biomass
Four pretreatment methods were conducted for comparison:
(1) Microwave heating with dilute acid: microwave pretreatment
was conducted in a microwave digestion system
(Shanghai Yiyao WX-4000, China). 0.5 g of algae biomass and
20 mL of dilute H2SO4 (1% v/v) were added to a polytetra-
fluoroethylene (PTFE) reactor (pH ¼ 1.4), sealed, and then
heated in a microwave to 140 C for 15 min [12]. (2) Steam
heating with dilute acid: 0.5 g of algae biomass and 20 mL of
dilute H2SO4 (1% v/v) were added to a flask (pH ¼ 1.4), the solution
was sealed, and then heated by steam to 140 C in an
autoclave for 15 min (3) Microwave heating with dilute alkali:
0.5 g of algae biomass and 20 mL of dilute NaOH (1% v/v) were
added to a PTFE reactor (pH ¼ 13). (4) Steam heating with dilute
alkali: 0.5 g of algae biomass and 20 mL of dilute NaOH (1% v/v)
were mixed in a flask (pH ¼ 13).
Cellulase and glucoamylase were added to the pretreated
solution for further hydrolysis: (1) cellulase addition: pH of
the pretreated solution was adjusted to 5.0 using 6 M NaOH