Microalgae biomass as a sustainable source for biofuel, biochemical and biobased value-added products: An integrated biorefinery concept

Microalgae are likely to become a part of our everyday diet in the near future as they are considered to be rich in proteins, carbohydrates, and high density lipoproteins. They will play a pivotal role in the food cycle of many people around the globe. Use of microalgae in treating wastewater is also one of the disciplines which are luring researchers as this contributes to a sustainable way of exploiting resources while keeping the environment safe. In addition, microalgal biomass also has the potential to be used as a feedstock for producing biofuel, bio fertilizers, pharmaceuticals, nutraceuticals and other bio-based products. This review presents the different value-added products obtained from microalgal biomass and the applicability of these products commercially.

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Valuable bioproducts obtained from microalgal biomass and their commercial applications: A review

The tension between a growing global demand for food, rising environmental impacts of agricultural intensification, and the uncertainty of future changes in our global climate highlight a crucial need for sustainable alternatives to maintain and increase agricultural productivity. Microalgae, including cyanobacteria, are renewable resources with a broad range of options for applications in agricultural settings. This review incorporates fundamental and applied aspects of microalgae impacting critical agricultural needs such as biological nitrogen fixation, soil phosphorus cycling, effects on soil microorganisms, plant growth promotion either by soil nutrient cycling and/or phytohormones or root associations, biocontrol, and soil stabilization. In this context, the review summarizes progress on microalgal biofilms and consortia as platforms for technological improvement. To complete the review, research needs for future advances are outlined, including evaluations on different types of soil and agroecological regions, scaled production of inoculum and methods of deployment, and further developments on applications such as biostimulants and soil reclamation and restoration.

Microalgae, soil and plants: A critical review of microalgae as renewable resources for agriculture

The increase in worldwide population observed in the last decades has contributed to an increased demand for food supplies, which can only be attained through an improvement in agricultural productivities. Moreover, agricultural practices should become more sustainable, as the use of chemically-based fertilisers, pesticides and growth stimulants can pose serious environmental problems and lead to the scarcity of finite resources, such as phosphorus and potassium, thus increasing the fertilisers’ costs. One possible alternative for the development of a more sustainable and highly effective agriculture is the use of biologically-based compounds with known activity in crops’ nutrition, protection and growth stimulation. Among these products, microalgal and cyanobacterial biomass (or their extracts) are gaining particular attention, due to their undeniable potential as a source of essential nutrients and metabolites with different bioactivities, which can significantly improve crops’ yields. This manuscript highlights the potential of microalgae and cyanobacteria in the improvement of agricultural practices, presenting: (i) how these photosynthetic microorganisms interact with higher plants; (ii) the main bioactive compounds that can be isolated from microalgae and cyanobacteria; and (iii) how microalgae and cyanobacteria can influence plants’ growth at different levels (nutrition, protection and growth stimulation).

https://www.mdpi.com/2076-3417/11/2/871/pdf

The Use of Microalgae and Cyanobacteria in the Improvement of Agricultural Practices: A Review on Their Biofertilising, Biostimulating and Biopesticide Roles

Fertilizers play a key role in yield if agriculture crops and their market value. Hence, large scale production of low cost, eco-friendly and broad spectrum fertilizers are mandatory. This study was to assess the effect of marine microalgal fertilizer on growth and yield of maize (Zea mays L.). The maize plants were raised in soil supplemented with two marine microalgae (Chlorella vulgaris and Spirulina platensis) along with cow dung manure for 75 days under green house condition. The marine microalgal treatment increased growth performance at the early stage of growth and improved yield characteristics, in addition to increased seed germination. Cow dung and two marine microalgae mixture treatment exhibited high growth and yield revealed the potential of the marine microalgae as fertilizer in cultivation of maize.

S. Kannadasan

Papers

The Impact of Using Microalgae as Biofertilizer in Maize (Zea mays L.)