Modern seafood processing practices result in amassment of a large volume of waste products, i.e., skin, head, tails, shells, scales, backbones, etc. These waste products may often encompass several high-value products which are still untapped due to the dearth of appropriate management. Moreover, inadequate disposal of waste also has negative implications on both environment and human health. This seafood waste often contains a huge amount of chitin, a polysaccharide that exhibits exceptional inherent characteristics including biocompatibility, biodegradability, antimicrobial, antitumor and antioxidant activities. The present review summarizes the existing methods for recovery of chitin and its derivatives from marine waste. The preparation of chitin nanoparticles was discussed along with blending of chitin and chitosan with other biopolymers. The recent trends of the application of chitin and chitosan nanostructures in various sectors were explored. This review is an attempt to highlight the extraction methods of chitin and chitosan from marine waste resources and its transformation into valuable commercial products as a solution to waste management.

Crop cultivation is crucial for the existence of human beings, as it fulfills our nutritional requirements. Crops and other plants are always at a high risk of being attacked by phytopathogens, especially pathogenic fungi. Although plants have a well-developed defense system, it can be compromised during pathogen attack. Chitinases can enhance the plant’s defense system as they act on chitin, a major component of the cell wall of pathogenic fungi, and render the fungi inactive without any negative impact on the plants. Along with strengthening plant defense mechanisms, chitinases also improve plant growth and yield. Chitinases in combination with recombinant technology can be a promising tool for improving plant resistance to fungal diseases. The applicability of chitinase-derived oligomeric products of chitin further augment chitinase prospecting to enhance plant defense and growth.

With the rapid population growth, there is an urgent need for innovative crop improvement approaches to meet the increasing demand for food. Classical crop improvement approaches involve, however, a backbreaking process that cannot equipoise with increasing crop demand. RNA-based approaches i.e., RNAi-mediated gene regulation and the site-specific nuclease-based CRISPR/Cas9 system for gene editing has made advances in the efficient targeted modification in many crops for the higher yield and resistance to diseases and different stresses. In functional genomics, RNA interference (RNAi) is a propitious gene regulatory approach that plays a significant role in crop improvement by permitting the downregulation of gene expression by small molecules of interfering RNA without affecting the expression of other genes. Gene editing technologies viz. the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (CRISPR/Cas) have appeared prominently as a powerful tool for precise targeted modification of nearly all crops’ genome sequences to generate variation and accelerate breeding efforts. In this regard, the review highlights the diverse roles and applications of RNAi and CRISPR/Cas9 system as powerful technologies to improve agronomically important plants to enhance crop yields and increase tolerance to environmental stress (biotic or abiotic). Ultimately, these technologies can prove to be important in view of global food security and sustainable agriculture.

The present study is a trail to integrate the phycoremediation and bioenergy production from microalgal species cultivated in the dairy wastewater (DWW). Higher biomass productivities for Chlorella pyrenoidosa (24.44 ± 8.02 mg L^-1d^-1), Anabaena ambigua (23.64 ± 5.69 mg L^-1d^-1) and Scenedesmus abundans (18.72 ± 2.06 mg L^-1d^-1) were recorded in 3:1 DWW over the control. The microalgal species have effectively reduced the BOD by 56%, COD by 77%, nitrate by 88%, and phosphate by 85% following 25 days of the cultivation in the 3:1 DWW. The total lipid content was 10.36, 13.13, and 16.93% of dry matter of biomass in C. pyrenoidosa, A. ambigua, and S. abundans, respectively following 25 days of cultivation in the 3:1 ratio of DWW. The biochemical characterization revealed that the protein content was 21.8% in C. pyrenoidosa, 17.73% in A. ambigua and 34.06% in S. abundans. The estimation of theoretical methane potential suggested that the microalgal species have the desirable possibility of biogas generation. The results have marked the achievability of an integrated process for the remediation and bioenergy production by the employment of microalgal species.

Growth of the industrial sector, a result of population explosion has become the root cause of environmental deterioration and has raised the concerns for efficient wastewater management and reuse. Photoautotrophic cultivation of microorganisms is a boon and considered as a potential biological treatment for remediation of wastewater as it sequesters CO₂ during growth. Photoautotrophs viz. cyanobacteria, micro-algae and macro-algae can photosynthetically assimilate the excessive pollutants present in the wastewater. The present review emphasizes on the achievability of microorganisms to bestow wastewater as the nutrient source for biomass production, which can further be reused for feed, food and fertilizers. To support this, various case studies have been cited that prove phycoremediation as a cost-effective and sustainable process over conventional wastewater treatment processes that requires high chemical load and more energy inputs.