Over the last decade, food waste has been one of the major issues globally as it brings a negative impact on the environment and health. Rotting discharges methane, causing greenhouse effect and adverse health effects due to pathogenic microorganisms or toxic leachates that reach agricultural land and water system. As a solution, composting is implemented to manage and reduce food waste in line with global sustainable development goals (SDGs). This review compiles input on the types of organic composting, its characteristics, physico-chemical properties involved, role of microbes and tools available in determining the microbial community structure. Composting types: vermi-composting, windrow composting, aerated static pile composting and in-vessel composting are discussed. The diversity of microorganisms in each of the three stages in composting is highlighted and the techniques used to determine the microbial community structure during composting such as biochemical identification, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE), terminal restriction fragment length polymorphism (T-RFLP) and single strand-conformation polymorphism (SSCP), microarray analysis and next-generation sequencing (NGS) are discussed. Overall, a good compost, not only reduces waste issues, but also contributes substantially to the economic and social sectors of a nation.

The agricultural sector generates approximately 1300 million tonnes of waste annually, where up to 50% comprising of raw material are discarded without treatment. Economic development and rising living standards have increased the quantity and complexity of waste generated resulting in environmental, health and economic issues. This calls for a greener waste management system such as valorization or recovery of waste into products. For successful implementation, social acceptance is an essential component with involvement of all local stakeholders including community to learn and understand the process and objective of the implementation. The agricultural waste product manufacturing industry is expected to increase with the growing demand for organic food. Thus, proper livestock and crop waste management is vital for environmental protection. It will be essential to successfully convert waste into a sustainable product that is reusable and circulated in the system in line with the green concept of circular economy. This review identifies the commercially produced crops by-product that have been considered for valorization and implemented green extraction for recovery. We highlight the importance of social acceptance and the economic value to agricultural waste recycling. Successful implementation of these technologies will overcome current waste management problems, reduce environmental impacts of landfills, and sustainability issue for farm owners.

Caulerpa racemosa (Forsskal) J. Agardh is a green seaweed used as food and folk medicine since ancient times in the Indo-Pacific region, particularly in southeast Asia. In this study, the proximate nutrient composition, phytochemical, anti-oxidant and anti-diabetic properties of sea grape C. racemosa collected from culture fishponds in Johor, Malaysia were analysed. The contents (dry weight basis) of carbohydrate, crude protein, crude lipids, ash and caloric value obtained were 33.42 ± 1.34%, 20.27 ± 0.14%, 4.20 ± 0.32%, 28.25 ± 0.27% and 2544.67 ± 7.04 cal g⁻¹, respectively. The amino acid score (AAs) and biological protein value (213.43 mg g⁻¹) indicated that C. racemosa presented a better protein quality. The most abundant fatty acids were C16:0 (palmitic acid: 63.27%), followed by C18:1 (oleic acid: 5.80%), and C18:2 ῳ6 (linoleic acid: 5.33%). The analysis of the ash content indicated that essential minerals and trace elements, such as Ca, Fe, and Mn, were present in the seaweed. The total phenolic content (TPC) and total flavonoid content (TFC) observed in the ethyl acetate extract were 17.88 ± 0.78 mg GAE g⁻¹ and 59.43 ± 2.45 mg QE g⁻¹, respectively. The ethyl acetate extract of C. racemosa demonstrated notable anti-diabetic activity in diabetic induced rats. The low (100 mg kg⁻¹) and high (200 mg kg⁻¹) doses of cultivated C. racemosa extract exhibited a significant decrease (p < 0.05) in blood glucose levels while preventing weight loss, reducing plasma AST, ALT levels as a sign of hepatoprotective effect and recording albumin levels similar to positive control in diabetic induced rats. The results support the usefulness of cultivated C. racemosa as a potential functional food.

Mangrove forests are salt-tolerant intertidal vegetation in tropical and subtropical areas. Mangrove ecosystems provide commercial products, valuable fisheries, and aquaculture resources, protect and stabilize coastlines, and are important carbon sinks. However, they are threatened globally by human activities such as deforestation, pollution, and development causing fragmentation between the well-preserved, restored, and disturbed mangrove forests. Despite this, mangroves can adapt and strive well and are notable well associated with microbial diversity. Here, we investigate the diversity of microbes in different environmental settings using preferred reporting items for systematic and meta-analyses (PRISMA) analysis for publications from Scopus and the Web of Science databases. We report publications since 1987, and observed an exponential increase in publications beginning in the year 2000, which may be associated with the development of molecular and sequencing technologies. Differences in bacterial diversity was observed across the well-preserved, restored, and disturbed mangrove environments. Disturbed mangrove forests had a higher diversity (70 unique taxon orders reported) compared to well-preserved (33 unique taxon orders reported) and restored forests (38 unique taxon orders reported). Based on our analysis, we found that the microbial community plays an important role in the survival and adaptability of mangroves under varying environmental conditions. Thus, there is a need and a lot of potential for research in the area of mangrove microbiology with reference to ecology, biogeochemistry, and geomorphology.