Comprehensive optimization of tropical biomass hydrolysis for nitrogen-limited medium-chain polyhydroxyalkanoate synthesis.

Expanding the use of tropical biomass wastes for nitrogen-limited fermentation was investigated, specifically, the production of medium chain length polyhydroxyalkanoates. Comprehensive central composite design was conducted to assess pH, temperature, biomass solid loading, cellulase loading and amylase loading and their impact on the hydrolysis of palm, coconut and cassava wastes. Glucose yields of 33.3, 31.7 and 79.0% wt. with respect to total glucose were found for palm, coconut and cassava, respectively. Importantly, the impact on the total nitrogen derived during enzymatic hydrolysis of these tropical biomass was described for the first time. The level of nitrogen needs to be properly controlled as high nitrogen would result in low carbon to nitrogen ratio leading to low polyhydroxyalkanoates accumulation, but low nitrogen would hinder growth of the biopolymer producer. Maximum hydrolysate nitrogen, were 1.80, 1.55 and 0.871 g/l for palm, coconut and cassava, respectively. Using the surface responses, biomass media designed for high carbon-to-nitrogen were produced and validated using Pseudomonas putida. Low glucose-carbon to nitrogen were found for palm and coconut after scale-up, leading to the majority of their polyhydroxyalkanoates not being biomass-derived. However, cassava-derived biopolymers were successfully accumulated at 9.01 and 7.13% wt. for total medium chain length polyhydroxyalkanoates and 10-carbon polyhydroxyalkanoates, respectively. This study provides an important foundation for the expansion of tropical biomass wastes for biopolymer production and other nitrogen-limited applications in general.

Valorization of Aquatic Weed and Agricultural Residues for Innovative Biopolymer Production and Their Biodegradation.

In this work, water hyacinths, bagasse and rice straw were valorized to produce an innovative biopolymer. Serial steps of extraction, bleaching and conversion of cellulose to be carboxymethylcellulose (CMC) as well as the last steps of blending and molding were performed. The CMC was mixed with tapioca starch solution by a ratio of 9:18, and a plastic sizer of glycerol was varied at 2%, 4% and 6% by volume. In addition, bioplastic sheets were further determined in their properties and biodegradation. The results revealed that bioplastics with 6% glycerol showed a high moisture content of 23% and water solubility was increased by about 47.94% over 24 h. The effect of temperature on bioplastic stability was found in the ranges of 146.28-169.25 °C. Furthermore, bioplastic sheets with 2% glycerol could maintain their shape. Moreover, for texture analysis, the highest elastic texture in the range of 33.74-38.68% with 6% glycerol was used. Moreover, bioplastics were then tested for their biodegradation by landfill method. Under natural conditions, they degraded at about 10.75% by weight over 24 h after burying in 10 cm soil depth. After 144 h, bioplastics were completely decomposed. Successfully, the application of water, weed and agricultural wastes as raw materials to produce innovative bioplastic showed maximum benefits for an environmentally friendly product, which could also be a guideline for an alternative to replace synthetic plastics derived from petroleum.

Techniques for analysing and monitoring during continuous bio-hydrogenation of kerosene from palm oils.

In this research work, analytical, experimental methods and monitoring techniques of bio-hydrogenated kerosene (BHK) production in continuous mode were presented. Two kinds of raw materials obtained from palm processing plant named as refined bleached deodorised palm oil (RPO) and palm kernel oil (PKO) were converted into BHK via hydrocracking reaction catalysed by Pd/Al2O3 catalyst in pilot scale. Firstly, both of RPO and PKO were pretreated by thermal technique. Subsequently, fatty acid compositions of palm oils were analysed by Gas Chromatography (GC). Then, hydrocracking reaction of RPO and PKO were separately conducted in continuous high pressure packed bed reactor (HPPBR). After reaction, crude-biofuel was refined into BHK via fractional distillation. In addition, some properties of BHK obtained from RPO/PKO such as were C, H, O elements, freezing point, flash points, total acid number and carbon distribution were analysed following the ASTM and UOP 915 standards.•Thermal pretreatment of refined bleached deoderised palm oil (RPO) and palm kernel oil (PKO).•Continuous hydrocracking reaction of palm oil was conducted in pilot scale.•Characterisation of bio-hydrogenated kerosene obtained from palm oil.

A novel process for biodiesel production from sludge palm oil.

Typically, sludge palm oil (SPO) which discharged from the palm oil refining process, is a low cost material of potential value, due to its high free fatty acid content. Accordingly, there is potential for upgrading low grade oil into valuable biofuel. In this work, we present a novel method for biodiesel production from SPO. The process consists of two steps (i) free fatty acid (FFA) extraction (ii) enzymatic esterification. Firstly, SPO was saponified by hydroalcoholic solution into soap and glycerol. Secondly, the FFAs obtained were further converted into biodiesel via enzymatic esterification catalyzed by immobilised alginate-PVA lipase beads. •Biodiesel production from sludge palm oil could be completed.•A modified fatty acid extraction was used for SPO fatty acid preparation.•Immobilised alginate-PVA lipase beads were used as biocatalyst for esterification reaction.