Microalgae:A potential alternative to health supplementation for humans

Microalgae has been consumed in human diet for thousands of years.It is an under-exploited crop for production of dietary foods.Microalgae cultivation does not compete with land and resources required for traditional crops and has a superior yield compared to terrestrial crops.Its high protein content has exhibited a huge potential to meet the dietary requirements of growing population.Apart from being a source of protein,presence of various bio-active components in microalgae provide an added health benefit.This review describes various microalgal sources of proteins and other bio-active components.One of the heavily studied group of bio-active components are pigments due to their anticarcenogenic,antioxidative and antihypertensive properties.Compared to various plant and floral species,microalgae contain higher amounts of pigments.Microalgal derived proteins have complete Essential Amino Acids(EAA)profiles and their protein content is higher than conventional sources such as meat,poultry and dairy products.However,microalgal based functional foods have not flooded the market.The lack of awareness coupled with scarce incentives for producers result in under-exploitation of microalgal potential.Application of microalgal derived components as dietary and nutraceutical supplements is discussed comprehensively.

Safety control of waste cooking oil:transforming hazard into multifarious products with available pre-treatment processes

The increase in worldwide vegetable oil consumption has produced a large increase in hazardous waste cooking oil(WCO)production.The improper disposal of WCO has been a significant problem from both an environmental and economic perspective.Therefore,it is advantageous to transform WCOs into valuable products efficiently and effectively in order to contribute towards the establishment of a circular economy.In this review,the current state of WCO is discussed in relation to WCO production and valorisation.The valorisation rate of each country can be categorised into three groups related to the consumption of vegetable oil,production and valorisation of WCO,as well as the production,conversion and valorisation factors.Before any valorisation and processing of WCO can be carried out,pretreatments are crucially needed in refining and upgrading WCOs,specifically to reduce their free fatty acid(FFA)contents.This could help to produce refined WCOs with appropriate feedstock properties suitable for value-added applications in oleochemical industries.Hence,several pretreatment methods(e.g.,solid impurities removal,FFA reduction,moisture removal)have been summarized and evaluated in depth.The transformation of WCO into valuable products including alkyd resin,green solvent,soap,plastics and plasticizer are also reviewed.Recent technological advances have made WCO feasible as sustainable feedstocks for oleochemical production,but not limited to biofuel production which in turn maximizes the value of this hazardous waste and turns WCO into a sustainable source.

Integrated microalgae culture with food processing waste for wastewater remediation and enhanced biomass productivity

Waste generation from food manufacturing facilities poses a serious hazard like environmental degradation, water pollution, and land pollution due to its high nutrient composition. Specifically, solid waste(powder) disposal requires additional energy sources in terms of scientific treatment, structured collection, and disposal packaging according to the safety regulation. Thus, this research discusses the viewpoint of integrating food processing waste as an organic carbon source with BG-11 medium for Chlorella vulgaris(FSP-E) growth. The food processing waste powders investigated in this study were obtained from milk, and biscuit manufacturing facilities. The culture medium was modified by combining both BG-11 and food processing waste powders to identify the optimal algal growth and biochemical content.Compared to the microalgae grown in BG-11 alone(IBG), the combination of biscuit waste and IBG produced higher biomass concentration(44%), with increased lipid(11%), protein(20%), and carbohydrate(57%) contents. Chlorella vulgaris was able to uptake nutrients from the culture medium with combination of food processing waste and IBG thus enhancing its growth. The results obtained also indicate that an integrated culture system using food processing waste and synthetic sources can generate energy out of waste by improving the bio-composition of the microalgae biomass.

Sonication and grinding pre-treatments on Gelidium amansii seaweed for the extraction and characterization of Agarose

Various prctreatments methods including sonication and grinding were perfonned on red seaweed Gelidium amansii for the subsequent extraction ofagarose. The agarose products are usually extracted from agar powder products from seaweeds. In this study, the agarose was extracted using a direct polyethylene glycol （PEG） method without the need to first process the agar from seaweed. The agar extract was frozen then thawed and mixed directly with PEG solution to precipitate the agarose. The quality of agarose obtained was evaluated through physico-chemical properties analysis which includes spectral technique （FTIR）, melting and boiling point, gel strength and sulfate content. These properties were compared with a non-pretreated sample and it was found that the addition of pretreatment steps improved the quality of agarosc but gave a slightly lower yield. The gel strength of pretreated samples was much higher and the sulfate content was lower compared to non-pretreated samples. The best pretreatment method was sonication which gave gel strength of 742 gcm - and sulfate content of 0.63%. The extraction of agarose can be further improved with the use of different neutralizing agents. Pretreating the seaweed shows potential in improving the quality of agarosc from seaweed and can be applied for thture extraction of the agarose.

Nature’s fight against plastic pollution:Algae for plastic biodegradation and bioplastics production

The increased global demand for plastic materials has led to severe plastic waste pollution,particularly to the marine environment.This critical issue affects both sea life and human beings since microplastics can enter the food chain and cause several health impacts.Plastic recycling,chemical treatments,incineration and landfill are apparently not the optimum solutions for reducing plastic pollution.Hence,this review presents two newly identified environmentally friendly approaches,plastic biodegradation and bioplastic production using algae,to solve the increased global plastic waste.Algae,particularly microalgae,can degrade the plastic materials through the toxins systems or enzymes synthesized by microalgae itself while using the plastic polymers as carbon sources.Utilizing algae for plastic biodegradation has been critically reviewed in this paper to demonstrate the mechanism and how microplastics affect the algae.On the other hand,algae-derived bioplastics have identical properties and characteristics as petroleum-based plastics,while remarkably being biodegradable in nature.This review provides new insights into different methods of producing algae-based bioplastics(e.g.,blending with other materials and genetic engineering),followed by the discussion on the challenges and further research direction to increase their commercial feasibility.