Biodegradable plastic is the preferred alternative to traditional plastic products due to its high degradability, decreased dependence on fossil sources, and decreased global pollution according to the accumulation of traditional plastic. In the current study, the optimization of biodegradable plastic synthesis was studied using biomass reinforcement materials. The reinforcement material is cellulose extracted from sawdust to prepare biodegradable plastic using the casting method. Response surface methodology using Box-Behnken Design is used to optimize the main parameters affecting the tensile strength and elongation at the break of the biodegradable plastic. These parameters are cellulose fiber addition, acetic acid addition, and the mass ratio of glycerol to starch. The maximum tensile strength and elongation were obtained at 4.45 MPa and 5.24%, respectively, using 5% cellulose fiber addition and 11.24% acetic acid addition with a 0.266 w/w glycerol to starch mass ratio. Various analyses were performed on the produced biodegradable plastic, including FTIR, SEM, and thermal stability. The biodegradability of the produced biodegradable plastic after immersing the soil for 10 days was about 90% higher than the traditional plastics. The produced biodegradable plastic has a moisture content of 4.41%, water absorption of 81.5%, water solubility of 24.6%, and alcohol solubility of 0%. According to these properties, the produced biodegradable plastic can be used in different industries as a good alternative to traditional plastics.

Modified clay granules were used to promote Azotobacter vinelandii cell adhesion. The A. vinelandii cells in the clay granules were used as a biofertilizer and a plant material. The production process was carried out under variable temperatures. The raw ingredients consisted of clay, sawdust waste, and spent coffee grounds in different ratios. Scanning electron microscopy (SEM) was used to analyze the microstructure. The results of the study showed the addition of sawdust waste and spent coffee grounds had increased the water absorption of the fired clay granules based on their porosity. However, increasing the firing temperature in the range of 900 degrees C- 1100 degrees C decreased the water absorption and porosity and increased the bulk density of the fired clay granules. A. vinelandii was enriched to be used as a cell suspension. The fired clay granules were immersed in a cell suspension to immobilize the A. vinelandii cells for 48 h. The SEM-based investigations indicated that the fired clay granules were suitable for containing A. vinelandii cells. The results demonstrated high viability of bacterial cells fixed in the fired clay granules at 2.7x 10(7) CFU/g. Furthermore, the test results of bacterial cells in the fired clay granules for marigold planting media revealed that it had effectively encouraged plant growth. The nitrogen-fixing bacterial cells in the clay granules obtained from this research were determined to be appropriate for use as an ecological soil replacement in the future.

The construction industry plays a significant role in shaping our environment and economy. However, it also substantially impacts the environment, including the depletion of natural resources, increased energy consumption, and waste generation. The green building trend has recently gained significant attention in recent years to mitigate the negative impacts of the building industry, focusing on sustainable materials and practices. One of the primary materials used in this field is clay brick, which leads to soil depletion over time. In this context, this study explores the potential of sawdust waste as a partial replacement for clay in brick production, aiming to reduce the depletion of natural resources while enhancing the properties and performance of the produced bricks. The study consists of two main phases: experimental and simulation. In the experimental phase, clay brick samples were produced by adding sawdust at different ratios (1%, 2%, 4%, 8%, and 10% of the raw weight), and various physical and mechanical properties of the produced samples were tested to ensure their suitability for construction use. Also, the thermal properties of the proposed brick were measured to investigate the effect of sawdust addition on brick thermal insulation. Consequently, thermal conductivity and specific heat were measured. In the simulation phase, DesignBuilder software (version 7.0.2) was used to investigate the impact of the proposed material on building envelope's performance and heat gain reduction. All experimental and simulation results were compared with the traditional clay brick measurements, which reveal a significant improvement in brick properties and performance with an increase in comprehensive strength of up to 192.3% and a reduction in energy consumption reaching 11.27%. The study results showed significant improvement in the properties and performance of the produced bricks, indicating the potential of using sawdust waste as a sustainable material for green buildings.