# An Overview of the Alternative Use of Seaweeds to Produce Safe and Sustainable Bio-Packaging
## 1 Introduction  
Seaweeds, also called marine macroalgae, are multicellular photosynthetic organisms that can be found in all aquatic environments. They are divided into three main groups according to their color, which is produced by the presence of pigments. Brown seaweeds (phylum Ochrophyta, class Phaeophyceae) have an abundance of pigments that vary from yellow to dark brown [1], while red seaweeds (phylum Rhodophyta) contain high amounts of carotenoids, chlorophyll (\(a\) and \(d\)), phycoerythrin, phycocyanin and allophycocyanin [2, 3]. Green seaweeds (phylum Chlorophyta) possess mainly chlorophyll, which has a key role in photosynthesis. Its greenish pigmentation conveys the typical green color in plants, algae, and cyanobacteria [4]. The variety of compounds present in seaweeds possess unique properties, which have positive effects on organisms; in fact, the use of seaweeds has been common since ancient times for alimentary and medicinal purposes, especially in Asian countries [5, 6, 7]. With the development of scientific research and new techniques, it has been possible to individuate compounds extracted from seaweeds and investigate their curative effects on human organisms, such as antioxidant, antimicrobial, antitumoral properties [8]. Moreover, seaweeds might be also employed in several industrial applications, such as the production of fertilizers [9, 10, 11], aquaculture feed, biofuels, application in wastewater treatments, or to produce innovative and ecologic materials to replace plastic equivalents [12, 13, 14], contributing towards a sustainable solution to protect the environment from the discharge of non-biodegradable plastic. Nowadays, plastic industries are responsible for a very high amount of plastic waste, especially due to the production of packaging; thus, it is of high priority that we find new, eco-friendly material to develop biodegradable packaging [15; 16; 17]. As the global population increases, the demand for plastic products also increases, along with the level of plastic waste in the environment [18]. More than eight million tons of plastic waste is dispersed into oceans every year, causing global environmental pollution and corrupting the proper functioning of ecosystems [19]. The growing necessity to decrease the use of petroleum-based plastic products has led research to look for new sources of raw material with the same characteristics of plasticizers, but also being biodegradable and non-harmful to human health and the environment. To attenuate the plastic waste, an ecologic alternative may be the development of \"bioplastics\"; this term refers to plastics derived from biological sources that are biodegradable and renewable. Bioplastics are easy to recycle, and their production requires less cost and energy relative to oil-based plastic [20]. Most of the food, cosmetic, and pharmaceutical products in the market are packaged in plastic, which takes more than 400 years to decompose, having a major impact on the environment. Therefore, the need for new sources of biodegradable film is a crucial point for the safeguard of our planet. Starch and cellulose are the main polysaccharides of vegetal origin tested for packaging materials [21]. Starch occurs widely in nature as reserve polysaccharide in plants; it has been considered for the development of biodegradable films as starch is easily obtained from natural sources, and is renewable, abundant, low cost, and has the ability to form an odourless, colourless, and transparent biofilm [22; 23; 24; 25]. The low oxygen permeability of the starch matrix makes it an interesting polysaccharide for food preservation [23; 26], even though so far limited applications have been developed as starches possess poor water barrier properties, a low melting point, and lower mechanical strength compared with petroleum-based plastics. Starch can be found in several vegetal sources, such as peas, rice, corn, potatoes, and tapioca [27; 28; 29; 30; 31].