Abstract. This study investigates the chemical and morphological characteristics of cassava peel (CP) biomass as a potential coagulant aid for turbidity, heavy metals and microbial removal. FE-SEM micrograph shown the surface of the CP samples was covered with smooth and globular in shaped of bound starch granules. FTIR spectra demonstrated that carboxyl and hydroxyl groups were present in abundance. Whereas analysis by XRF spectrometry indicated the CP samples contain Fe 2 O 3 and Al 2 O 3 which might contribute to its coagulation ability. The features of CP obtained from this study promotes the feasibility of CP to be further developed and studied to produce effective coagulant aid as sustainable alternative to reduce the usage of chemical coagulants.

Tons of anthropological activities contribute daily to the massive amount of lignocellulosic wastes produced annually. Unfortunately, their full potential usually is underutilized, and most of the biomass ends up in landfills. Lignocellulolytic enzymes are vital and central to developing an economical, environmentally friendly, and sustainable biological method for pre-treatment and degradation of lignocellulosic biomass which can lead to the release of essential end products such as enzymes, organic acids, chemicals, feed, and biofuel. Sustainable degradation of lignocellulosic biomass via hydrolysis is achievable by lignocellulolytic enzymes, which can be used in various applications, including but not limited to biofuel production, the textile industry, waste treatment, the food and drink industry, personal care industry, health and pharmaceutical industries. Nevertheless, for this to materialize, feasible steps to overcome the high cost of pre-treatment and lower operational costs such as handling, storage, and transportation of lignocellulose waste need to be deployed. Insight on lignocellulolytic enzymes and how they can be exploited industrially will help develop novel processes that will reduce cost and improve the adoption of biomass, which is more advantageous. This review focuses on lignocellulases, their use in the sustainable conversion of waste biomass to produce valued-end products, and challenges impeding their adoption.

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This work aimed to develop green biodegradable film using red seaweed (Kappaphycus alvarezii) as a base matrix and calcium carbonate (CaCO3) as a filler to enhance the properties of the red seaweed material for plasticulture purpose. CaCO3 which was produced by microbially induced precipitation (MB-CaCO3) using Bacillus sphaericus, was characterized and compared with the commercial CaCO3 (CCaCO3). FESEM image revealed that the size of MB-CaCO3 was smaller and more uniform compared to CCaCO3. FTIR and XRD analyses confirmed the existence of crystalline polymorph of calcite in MB-CaCO3, which contained a higher percentage of calcite than CCaCO3. However, the crystallinity and thermal stability of MB-CaCO3 was lower than CCaCO3. From the results of physical, mechanical and thermal properties of composite films filled with CCaCO3 and MB-CaCO3 fillers, the optimum loading of CCaCO3 and MB-CaCO3 was found at 0.1% and 0.15%, respectively. Composite films filled with MB-CaCO3 promote brighter film, better water barrier, hydrophobicity and biodegradability compared to CCaCO3. Since the effect of MB-CaCO3 on film functional properties was comparable to CCaCO3, it can be used as an alternative to CCaCO3 as inorganic filler for composite films in agriculture applications.

Laboratory-scale experiments were carried out to investigate the removal efficiency of iron and manganese from groundwater using limestone filter assisted with iron-oxidized bacteria. Column studies were conducted using limestone with a particle size between 0.6 and 2.36 mm and run at different operation times with a flow rate of 4 L/h and retention time of 2.94 min. Iron-oxidized bacteria were extracted from groundwater samples and cultured in an agar plate with nutrient agar solution for the bacteria duplication. Iron-oxidized bacteria resulted in a change in limestone composition as shown in X-ray diffraction and scanning electron microscope results due to the destruction of limestone particles for easier adsorption. Results show that the limestone filter assisted with IOB has better performance than the filter of limestone alone, in removing Fe and Mn. The maximum removal efficiency of Fe and Mn was 81.72% and 83.63%, respectively, at an operation time of 2 h. Ironoxidized bacteria catalyze the oxidation of adsorption process as well as the soluble Fe(II) and Mn(II) to insoluble Fe(III) and Mn(IV). In addition, the results revealed that the increase in operation time resulted in increasing the rate of Fe and Mn oxidation. Operation time was found to be an influential factor on the removal process where the optimum values of pH and turbidity were achieved at 1.5 h of operation time. Furthermore, Fe concentration was decreased with the increase in operation time, while Mn concentration was increased with the increase in operation time. Overall, this study demonstrates that the limestone filter assisted with iron-oxidized bacteria is an effective filtration process for Fe and Mn removal in groundwater.

Discovering novel bacterial strains might be the link to unlocking the value in lignocellulosic bio-refinery as we strive to find alternative and cleaner sources of energy. Bacteria display promise in lignocellulolytic breakdown because of their innate ability to adapt and grow under both optimum and extreme conditions. This versatility of bacterial strains is being harnessed, with qualities like adapting to various temperature, aero tolerance, and nutrient availability driving the use of bacteria in bio-refinery studies. Their flexible nature holds exciting promise in biotechnology, but despite recent pointers to a greener edge in the pretreatment of lignocellulose biomass and lignocellulose-driven bioconversion to value-added products, the cost of adoption and subsequent scaling up industrially still pose challenges to their adoption. However, recent studies have seen the use of co-culture, co-digestion, and bioengineering to overcome identified setbacks to using bacterial strains to breakdown lignocellulose into its major polymers and then to useful products ranging from ethanol, enzymes, biodiesel, bioflocculants, and many others. In this review, research on bacteria involved in lignocellulose breakdown is reviewed and summarized to provide background for further research. Future perspectives are explored as bacteria have a role to play in the adoption of greener energy alternatives using lignocellulosic biomass.

The agricultural and food processing industries generate a significant portion of residues, refuse and waste. Conversion of these wastes into useful end product would be beneficial not only to the economy but also the environment as it reducing the solid waste disposal problem. The present study was aimed to investigate the performance of cassava peel starch (CPS) extracted from cassava peel waste in combination with alum to act as dual coagulant for turbidity removal in raw water from Sembrong dam. Comparative studies by employing both alum and CPS as primary coagulant using several series of Jar test were also conducted. Results showed that the usage of alum-CPS as dual coagulant not only enhanced the turbidity removal with maximum achievement up to 91.47%, but also significantly improve the coagulation process by reducing both alum dosage and settling time up to 50% which indicates broad prospects to be further developed as emerging green coagulant.

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