Evaluating carbon, nitrogen and heavy metal content in different agriculture biomass for mushroom substrate

Abstract

A substrate is an essential requirement for mushroom cultivation as it provides the nutrients for the growth of the mushroom mycelia to produce fruiting bodies. Abundant agricultural biomass such as oil palm waste, paddy straw, timber and sugarcane bagasse, lead to the uses for the mushroom substrates. These abundant biomasses are very less used for human activities whereas the remaining part refers to agriculture waste. The agriculture waste can be used as alternative substrates for mushroom cultivation due to the commercial substrates of rubber sawdust prices have been increasing that can affect the cost of the mushroom production. However, choosing different alternative substrates will have a different effect on the yields and quality of the mushrooms. The mushroom substrates mainly composed of the sources of carbon and nitrogen that act as the essential element for the growth of the mushroom. Apart from the variation of carbon and nitrogen content in the mushroom substrates, the substrates might contain toxic metal that can contaminate the fruiting bodies through the nutrient uptakes. Mushrooms have been observed to absorb and store variety of chemical elements where they can lead to contamination towards the edible fruiting bodies. Hence, this study choose different agricultural biomass of paddy straw and oil palm frond with the commercial substrate of sawdust in order to analyse the content of the substrates for mushroom cultivation suitability. Results were demonstrated that paddy straw have potential as alternative substrates for mushroom cultivation based on the C/N ratio value (0.5907) due to the high nitrogen content (84.92±9.71%) whereas mushroom need low C/N for better growth. The heavy metal content for paddy straw is follow WHO/FAO safe limit quantity Cu, Fe, Zn and Pb were 0.1433mg/L, 1.5993mg/L, 0.8090mg/L and 0.0233mg/L, respectively. However, arsenic content for paddy straw recorded the lowest amount between the treatments which is 2.0423mg/L and nearly reaching the permissible limit.