Drying Characteristics of <i>Chlorella pyrenoidosa</i> Using Oven and its Evaluation for Bio-Ethanol Production

Landfill-mined soil-like fraction (LMSF) use in biopolymer composting: Material pre-treatment, bioaugmentation and agricultural prospects

Polylactic Acid (PLA) based compostable bioplastic films degrade under thermophilic composting conditions. The purpose of our study was to understand whether sample pre-treatment along with bioaugmentation of the degradation matrix could reduce the biodegradation time under a simulated composting environment. Sepcifically, we also explored whether the commercial composts could be replaced by landfill-mined soil-like fraction (LMSF) for the said application. The effect of pre-treatment on the material was analysed by tests like tensile strength analysis, hydrophobicity analysis, morphological analysis, thermal degradation profiling, etc. Subsequently, the degradation experiment was performed in a simulated composting environment following the ASTM D5338 standard, along with bioaugmentation in selected experimental setups. When the novel approach of material pre-treatment and bioaugmentation were applied in combination, the time necessary for 90% degradation was reduced by 27% using compost and by 23% using LMSF. Beyond the improvement in degradation rate, the water holding capacity increased significantly for the degradation matrices. With pH, C: N ratio and microbial diversity tested to be favourable through 16s metabarcoding studies, material pre-treatment and bioaugmentation allow LMSF to not only replace commercial compost in polymer degradation but also find immense application in the agricultural sector of drought-affected areas (for better water retention) after it has been used for PLA degradation.

Experimental and modelling studies of convective and microwave drying kinetics for microalgae

Conventional microalgal drying consumes huge time and contributes to 60-80% of downstream process costs. With the aim to develop an effective and rapid drying process, the present study evaluated the performance of microwave based drying (MWD) with a power range of 360-900 W and compared with the conventional oven drying (OD) at 40-100 °C. MWD was found to be efficient due to uniform and volumetric heating because of dipolar interaction, with an effective diffusivity of 0.47 × 10^-9-1.63 × 10^-9 m² s^-1, comparatively higher than OD. Activation and specific energy of 32.43 W g^-1 and 42.9-56.07 kWh kg^-1 was projected respectively, and a falling rate period with best fit for Newton and Henderson-Pabis model was observed for MWD. Uniform heating from internal sub-surface avoided cell distress, resulting in 14.4% higher lipid yield and significant preservation of biochemical components that can be processed into bioenergy and valuable products in microalgal biorefinery.