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This study focuses on mitigating the socio-economic and environmental damage of the invasive macroalga Rugulopteryx okamurae and counteracting the pollution from petroleum-based plastics by using the alga as a feedstock for polyhydroxybutyrate (PHB) production. The enzymatic hydrolysis of R. okamurae, non-pretreated and hydrothermally acid-pretreated (0.2 N HCl, 15 min), was carried out, reaching reducing sugar (RS) concentrations of 10.7 g/L and 21.7 g/L, respectively. The hydrolysates obtained were used as a culture medium for PHB production with Cupriavidus necator, a Gram-negative soil bacterium, without supplementation with any external carbon and nitrogen sources. The highest yield (0.774 g PHB/g RS) and biopolymer accumulation percentage (89.8% cell dry weight, CDW) were achieved with hydrolysates from pretreated macroalga, reaching values comparable to the highest reported in the literature. Hence, it can be concluded that hydrolysates obtained from algal biomass hydrothermally pretreated with acid have a concentration of sugars and a C/N ratio that favour PHB production. [ABSTRACT FROM AUTHOR]

The production of bioplastics from renewable materials has gained interest in recent years, due to the large accumulation of non-degradable plastic produced in the environment. Here, sugar beet pulp (SBP) is evaluated as a potential raw material for the production of bioplastics such as polylactic acid (PLA) and polyhydroxyalkanoates (PHAs). SBP is a by-product obtained in the sugar industry after sugar extraction from sugar beet, and it is mainly used for animal feed. It has a varied composition consisting mainly of cellulose, hemicellulose and pectin. Thus, it has been used to produce different value-added products such as methane, hydrogen, pectin, simple sugars, ethanol, lactic acid and succinic acid. This review focuses on the different bioprocesses involved in the production of lactic acid and PHAs, both precursors of bioplastics, from sugars derived from SBP. The review, therefore, describes the pretreatments applied to SBP, the conditions most frequently used for the enzymatic hydrolysis of SBP as well as the fermentation processes to obtain LA and PHAs. [ABSTRACT FROM AUTHOR]

It is well-known that brown macroalgae can be used as a source of valuable sugars with different biological activities, but its polymeric macrostructures should be hydrolyzed for obtaining an acceptable yield. This study deals with the production of free sugars by the enzymatic hydrolysis of optimized biologically pretreated brown seaweed. The biological pretreatment was carried out using solid-state fermentation (SSF) with a white root fungus species (Aspergillus awamori). For this purpose, different temperature growth conditions (30°C and 50°C) and inoculum concentrations (106; 107 and 108 spores/g of dried solid) were tested for 20 days of the SSF process. In addition, different dosages of commercial hydrolytic enzyme cocktail Cellic® Ctec2 were tested for enzymatic hydrolysis (EH) of D. dichotoma at a solid/liquid ratio of 2.2% w/v. Finally, biologically pretreated samples at optimum conditions (30°C and inoculum size of 108 cel/mL) were hydrolyzed with commercial Cellic® Ctec2 at the optimum dosage (112FPU/g). The maximum reducing sugars concentration measured in the hydrolysates was 80 g/kg biomass. Further investigations increasing the solid-liquid ratio and reducing the enzyme dosage are necessary for the complete optimization of sugar production from D. dichotoma. [ABSTRACT FROM AUTHOR]