Valorization of brewer's spent grains to produce nutrient biodegradable plant pot

The study explored the use of brewery spent grain (BSG) for creating a biodegradable pot that releases nutrients. Sixteen different composite formulations were prepared using clay as a filler, polyvinyl acetate (PVAc) as a binder, and glycerol as a plasticizer. The composition ratio was critical in achieving a homogeneous matrix and pot formability. The T10 and T14 pot formulations, with a clay:PVAc:glycerol ratio of 100:50:25, performed best and were chosen for soil burial testing. The impact of BSG content on biodegradability and mineralization was investigated. T10 showed twice the degradation of T14 after 45 days in soil due to higher BSG content, resulting in greater weight loss. Soil pH and electrical conductivity remained constant, indicating minimized soil acidity. Although a solid matrix hindered water penetration and reduced soil microflora, cracking and erosion were observed. Organic matter and total nitrogen in adjacent soil significantly increased from Day0 to Day45 for both T10 and T14, indicating nutrient release during biodegradation. The study concluded that BSG could be used to produce biodegradable pots with nutrient release potential, providing a sustainable alternative to conventional plastic seeding bag or pot.