ABSTRACT
Antibiotic resistance in bacteria has emerged as a serious public health threat worldwide. Aquatic environments including irrigation-purpose wastewaters facilitate the emergence and transmission of antibiotic-resistant bacteria and antibiotic resistance genes leading to detrimental effects on human health and environment sustainability. Considering the paramount threat of ever-increasing antibiotic resistance to human health, there is an urgent need for continuous environmental monitoring of antibiotic-resistant bacteria and antibiotic resistance genes in wastewater being used for irrigation in Indian agro-ecosystems. In this study, the prevalence of antibiotic resistance in Gram-negative bacteria isolated from irrigation-purpose wastewater samples from Sirmaur and Solan districts of Himachal Pradesh was determined. Bacterial isolates of genera Escherichia, Enterobacter, Hafnia, Shigella, Citrobacter, and Klebsiella obtained from 11 different geographical locations were found to exhibit resistance against ampicillin, amoxyclav, cefotaxime, co-trimoxazole, tobramycin, cefpodoxime and ceftazidime. However, all the isolates were sensitive to aminoglycoside antibiotic gentamicin. Enterobacter spp. and Escherichia coli showed predominance among all the isolates. Multidrug-resistance phenotype was observed with isolate AUK-06 (Enterobacter sp.) which exhibited resistant to five antibiotics. Isolate AUK-02 and AUK-09, both E. coli strains showed resistant phenotypes to four antibiotics each. Phenotypic detection revealed that six isolates were positive for extended-spectrum ß-lactamases which includes two isolates from Enterobacter spp. and E. coli each and one each from Shigella sp. and Citrobacter sp. Overall, the findings revealed the occurrence of antibiotic resistant and ESBL-positive bacterial isolates in wastewaters utilized for irrigation purpose in the study area and necessitate continuous monitoring and precautionary interventions. The outcomes of the study would be of significant clinical, epidemiological, and agro-environmental importance in designing effective wastewater management and environmental pollution control strategies.
ABSTRACT
The current era of industrialization includes a constantly increasing demand for plastic products, but because plastics are rarely recycled and are not biodegradable plastic pollution or "white pollution" has been the result. The consumption of petroleum-based plastics will be 20% of global annual oil by 2050, and thus there is an inevitable need to find an innovative solution to reduce plastic pollution. The biodegradable and environmentally benign bioplastics are suitable alternative to fossil-based plastics in the market due to sustainability, less carbon footprint, lower toxicity and high degradability rate. Microalgal species is an innovative approach to be explored and improved for bioplastic production. Microalgae are generally present in abundant quantity in our ecosystem, and polysaccharide in the algae can be processed and utilized to make biopolymers. Also, these species have a high growth rate and can be easily cultivated in wastewater streams. The review aims to determine the recent status of bioplastic production techniques from microalgal species and also reveal optimization opportunities involved in the process. Several strategies for bioplastic production from algal biomass are being discussed nowadays, and the most prominent are "with blending" (blending of algal biomass with bioplastics and starch) and "without blending" (microalgae as a feedstock for polyhydroxyalkanoates production). The advanced research on modern bioengineering techniques and well-established genetic tools like CRISPR-Cas9 should be encouraged to develop recombinant microalgae strains with elevated levels of PHA/PHB inside the cell.
