Waste mushroom substrate-derived biochar for mushroom cultivation

What is it about?

Spent mushroom substrate (SMS), largely produced as an agriculture waste from mushroom cultivation, was transformed into biochar via microwave vacuum pyrolysis under different ratios of SMS to microwave absorbent (1:1, 1:2, and 1:3). The biochar was then examined for its potential to be re‐used in mushroom cultivation as a growth medium added to conventional mushroom baglog (plastic bag with mushroom seeds and culture substrates containing rice straw, sawdust, lime and water), with emphasis on its ability to form mycelium – a fungus that grows into mushroom from its seeds.

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Why is it important?

We found that the pyrolysis generated up to 36 wt% biochar yield with a large adsorption area (up to 215 m2/g) and less water percentage (4 wt%), indicating that many adsorption sites are available on which mushroom seeds, nutrient and water can be adsorbed onto in order to form mycelium (and subsequently mushroom). The biochar added to grow mushroom in baglog recorded a higher water retention percentage (up to 59%), a higher mycelium colonization length in 8 days (6.3 cm), coverage area (up to 259 cm2) and total mycelium growth volume (317 cm3), and resulted in a higher yield of mushroom (200 g/month) than that recorded in the conventional baglog without biochar (160 g/month).