Search

Seaweeds are found abundance in most seashores. They contain relatively high lipid contents and are exhibiting medicinal properties. The present work focused on the use of seaweed species Ulva linza, U. tubulosa, U. fasciata, U. rigida, and U. reticulate to synthesize Mn2ZnO4 composite nanoparticles. The later was utilized for biodiesel production and its antibacterial potential was also assessed. Heterogeneous mixed metal oxides are suitable catalysts for biodiesel production due to ease of separation, reusability and environmental friendliness. The employment of multi-resistant organisms (MROS) is of major importance in modern medicines. Thus there is an extreme need for potential antibacterial alternatives such as metal oxides. Mn2ZnO4 nanoparticles were synthesized by using a co-precipitation method. The crystalline behavior and morphological characterizations were carried out through XRD, FE-SEM, Raman Spectra and FT-IR respectively. The particle size was found to be 42 nm. Fatty Acid Methyl Ester (FAME) produced from Ulva species was analyzed by gas chromatography and physical parameters were also determined. The yields were as follows: U. linza 72.3%, U. tubulosa 72%, U. fasciata 70.6%, U. rigida 70.4%, and U. reticulate 71.5%. The antibacterial potential of synthesized Mn2ZnO4 nanoparticles after transesterification, showed strong antibacterial activity against both gram positive and gram negative bacteria and were found to be comparable to commercially available antibiotics. To assess their antibacterial efficiency, the minimum inhibition concentration was measured. The used catalysts exhibit high efficient catalytic activity on degrading methylene blue under UV irradiation.

An effort in contributing to the reduction of fossil resource dependence along with utilization of lignocellulosic wastes, will be a beneficial approach in biofuel production. These approaches will aid in sustainable waste management and will contribute to economic feasibility. This study probed the exploitation of abundant, non-edible lignocellulosic wastes such as sugarcane bagasse and rice husk as a low-cost carbon source for the cultivation of oleaginous yeast isolates and lipid accumulation, respectively. The hydrolysis of the lignocellulose was explored by steam explosion alone to reduce the inflation of toxic compounds like hydroxy methyl furfural (HMF), furfural, and acetic acid. This optimization study investigated the effects of carbon sources (sugarcane bagasse hydrolysate, rice husk hydrolysate, and commercial glucose), nitrogen sources, and pH on biodiesel production using central composite design (CCD), and achieved a full factorial design. All the three variables were found to have a positive influence on biodiesel production. Greater biomass production was achieved by SY2 (Pichia kudriavzevii) with a value of −8.37 ± 0.067 g/L when sugarcane bagasse hydrolysate was used. Maximum lipid content of 37.99 ± 0.003% was attained by the strain G5 (Meyerozyma guilliermondii) upon using sugarcane bagasse hydrolysate in the production medium and higher lipid accumulation of 2.39 ± 0.003 g/L was attained by SY2 (Pichia kudriavzevii) upon using rice husk hydrolysate. Analysis of the kinematic properties of FAME (Fatty Acid Methyl Esters) was obtained using Biodiesel analyzer V1.1. software, and affirmed the values similar to the biodiesel standard values (EN 14214, ASTM, IS 15607). The kinematic studies used to figure out the quality of the biodiesel, revealed that FAME produced by SY2 (Pichia kudriavzevii) strain showed greater oxidation stability (37.17 h) and better kinematic viscosity (1.3084). These properties ensured that SY2 (Pichia kudriavzevii) strain was appropriate in producing exceptional quality biodiesel. Hence, the present investigation tried to prove the competency of the yeast isolates in sustainable biodiesel production by engaging agronomic wastes.