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Konversi
Published by Universitas Lambung Mangkurat
ISSN : 23023686     EISSN : 25413481     DOI : -
Core Subject : Education,
Education
Arjuna Subject : -
Articles 271 Documents
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Utilization of pineapple stems as biocatalysts in the production of coconut oil using the enzymatic method Fanani, Nurull; Nisa, Nur Ihda Farikhatin; Siswoyo, Deddy Kurniawan Putra; Tuhuloula, Abubakar; Putri, Novy Pralisa
Konversi Vol 14, No 1 (2025): APRIL 2025
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v14i1.22233

Abstract

The utilization of pineapple fruit stems as a by-product of the agricultural process has not been optimally utilized. Meanwhile, pineapple fruit stems have promising economic potential in the field of biotechnology and food processing. This is because pineapple fruit stems contain bromelain enzyme which is quite high compared to ripe fruit flesh, which is around 0.1-0.6%. This bromelain enzyme functions as a biocatalyst in breaking down protein and fat through the hydrolysis reaction of coconut oil. So to find out the catalytic activity of bromelain enzyme in pineapple fruit stems, the process of making coconut oil is carried out enzymatic method through variable addition of doses of 20, 30, 40, and 50% of the weight of coconut milk and enzymatic time duration of 6, 12, 18, and 24 hours. Based on the research results, the best variable is the addition of 30% biocatalyst dose and 24 hours of enzymatic process with the highest yield percentage of 67.9% and product characteristics that have met SNI 7381: 2008. This shows that pineapple fruit stems have the potential as a good biocatalyst in making coconut oil as well as providing added value to pineapple fruit stems in an effort to verify agricultural waste.
Organic Linker Functionalization with Chemical Groups: A Theoretical Approach Anyama, Chinyere Ayi; Anyama, Emmanuel Ayi; Ayi, Ayi Anyama
Konversi Vol 14, No 2 (2025): OCTOBER 2025
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v14i2.23799

Abstract

AbstractPhenyl-2-pyridyl ketoxime (herein PPKO) with formula C12H10N2O and its CH3, OH, NH2 and  NO2 modified forms were optimized with Gaussian 09 using B3LYP (Beckes’ 3-parameter exchange with Lee-Yang-Parr correlation energy) functional and 6-311+ G(d,p) basis set. Their structural, spectroscopic and molecular properties were  investigated at same molecular level. The HOMO-LUMO energy was used to calculate the quantum descriptors to gain insight into their  energy gap, reactivity and  stability.  From our result, we observed a narrowing of the energy gap of PPKO (0.184 eV) to 0.180 eV, 0.176 eV, 0.166 eV and 0.149 eV in CH3-PPKO, OH - PPKO, NH2-PPKO and NO2-PPKO respectively. The optical performance was calculated with Time dependent Self Consistent Field (TD-SCF) and Integral equation formalism polarizable continuum model (IEF-PCM). From our result, the absorption wavelength of  PPKO (283 nm) was extended to 284 nm, 307 nm and 356 nm in OH-PPKO, NH2-PPKO and NO2-PPKO respectively. This observed red shift in absorption wavelength is attributed to π-π* transitions. From the simulated FT-IR, the O-H stretch was observed at 3600 cm-1 , 3603 cm-1, 3605 cm-1, 3609 cm-1 and 3585 cm-1 for PPKO, CH3-PPKO, OH-PPKO, NH2-PPKO and NO2-PPKO respectively. The perturbation energy which gives insight into intra molecular and inter molecular interactions between donor and acceptor orbitals was calculated with respect to the second-order Fock matrix perturbation theory.  NO2-PPKO showed the greatest perturbation energy (250.92 k/cal/mol) from transitions between π*C1-N6 and π*C4-C5 (donor and acceptor orbitals respectively).  Key Words:Ligands, Functionalization, MOFs, Energy gap, Reactivity.  
The effect of microwave power, extraction time and solvent ratio of microwave assisted extraction (MAE) method on the yield of pectin from Nephelium lappaceum Daffa Athallah, Talitha Ayu; Kurnianto, Muhammad Alfid; Priyanto, Anugerah Dany; Munarko, Hadi; Putra, Andre Yusuf Tisna; Wicaksono, Luqman Agung
Konversi Vol 14, No 1 (2025): APRIL 2025
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v14i1.22033

Abstract

Pectin is a complex polysaccharide that is widely used in the food, pharmaceutical, and cosmetic industries as a thickening agent, stabilizer, and emulsifier. Extraction methods such as hot acid extraction have limitations in terms of time efficiency and yield. Therefore, the Microwave-Assisted Extraction (MAE) method is a faster and more efficient alternative. Microwave-assisted extraction is a potential method for pectin extraction from rambutan binjai peel. Conventional extraction methods (direct heating) are widely used, but have drawbacks such as long process time, low yield, and the risk of pectin degradation. Environmentally friendly or green extraction processes are now being applied, one of which is microwave-assisted extraction.Based on research results, it is known that microwave pectin extraction has a higher yield and shorter extraction time compared to conventional methods. The best extraction results were obtained at a power of 540 Watts, with an optimal extraction time of 11 minutes and a solvent ratio of 1:20, with the highest yields being 7.53%, 7.11%, and 6.48%, respectively. The objectives of this study were (i) to determine the best microwave power in the extraction process, (ii) to determine the optimal extraction time, and (iii) to determine the best solvent ratio in the extraction process.
Ultrasound-assisted liquid biphasic extraction of fucoidan from Sargassum sp. Fachri, Boy Arief; Labibah, Jovita; Luthfiana, Zakia; Ansori, Ansori; Putri, Ditta
Konversi Vol 15, No 1 (2026): APRIL 2026
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v15i1.25502

Abstract

Sargassum sp.. is an essential source of fucoidan. This work aims to extract fucoidan from Sargassum sp.. using a liquid biphasic system assisted by ultrasonics. It observes the effects of various process parameters on fucoidan yield, determines the optimum extraction conditions, and develops a model for extraction kinetics. In the experiment, 80-mesh Sargassum sp.. powder is ultrasonically treated in a 2-propanol solution. Furthermore, the extract is separated by the addition of a K₂HPO₄ solution, which forms a two-phase system. Following the process, the CaCl2 is introduced to separate the alginate. Afterwards, ethanol is added to the resulting filtrate to precipitate fucoidan. This approach highlights techniques for efficient extraction and separation of fucoidan from Sargassum sp.. The process parametperaturaers included extraction time (10, 15, and 20 minutes), ultrasonic power (60%, 65%, and 70%), and the Sargassum-to-solvent ratio (0.03, 0.04, and 0.05 g/mL). This work confirms that FTIR and HPLC techniques successfully identified fucoidan. The highest yield, 14.1%, was achieved with a Sargassum-to-solvent ratio of 0.04 g/mL, an extraction time of 20 minutes, and an ultrasonic power of 70%. The results indicate that extraction time is a significant factor compared to power and the Sargassum-to-solvent ratio. The diffusion coefficient (Dₑ) of 1.425118 × 10⁻² m²/s suggests relatively rapid diffusion under the applied extraction conditions.
Optimization of aerobic fermentation of solid fertilizer from goat manure using response surface methodology (RSM) Mandriana, Rizna Aini; Mafachir, Muhammad Tajul; Billah, Mu'tasim; Sari, Ni Ketut; Kurnianti, Ely; Suprihatin, Suprihatin
Konversi Vol 15, No 1 (2026): APRIL 2026
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v15i1.25810

Abstract

The increase in the goat population in Panceng District has resulted in an increase in the volume of goat waste which has the potential to pollute the environment if not managed properly. Goat manure has good nutrient content, but the high initial C/N ratio (30.47) indicates that the material is not yet stable and requires a fermentation process. This study aims to optimize the aerobic fermentation process using the Response Surface Methodology (RSM) with varying air flow rates (5–25 L/min) and oxidation times (16–24 days). The process was carried out in an in-vessel non-flow reactor with an active aeration system. Carbon content analysis using the Walkley–Black Modified Spectrophotometric method and nitrogen content analysis using the Kjeldahl Method and water content using the gravimetric method. The results showed that increasing the air flow rate and oxidation time caused a significant decrease in the C/N ratio from 30.47 to 11.52–17.62. The optimum conditions were obtained at an air flow rate of 20 L/min and an oxidation time of 22 days with a C/N ratio of 12.4769 and a water content of 23.3309%, and a desirability value of 1. These results show that optimization using RSM is able to produce solid organic fertilizer that meets SNI standards (<20).
Adsorption behavior of Cu(II) on microwave-activated lemongrass-derived carbon: isotherm and kinetic modeling Ni'mah, Lailan -; Mahfud, Mahfud -; Juliastuti, Sri Rachmania; Muis, Ramdiana -
Konversi Vol 15, No 1 (2026): APRIL 2026
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v15i1.25556

Abstract

This study evaluates the adsorption performance, equilibrium behavior, and kinetic properties of Cu ions using microwave-activated carbon derived from lemongrass for acid mine drainage treatment. The precursor was carbonized at 300 °C for 2 h and subsequently activated under microwave irradiation to enhance its physicochemical properties. Batch experiments were conducted with adsorbent dosages of 2–7 g and a fixed contact time of 60 min, and the remaining Cu concentration was measured by atomic absorption spectrophotometry. An optimal dosage of 4 g achieved the highest removal efficiency of 54.18%. Equilibrium data were analyzed using the Langmuir and Freundlich isotherm models, with the Langmuir model providing a better fit, yielding a maximum adsorption capacity (qmax) of 3.60 mg/g, a Langmuir constant (KL) of 43,27 mol/L, and an R² of 0,9825, compared with KF 3,46 and an R² of 0,9677 for the Freundlich model. These findings indicate predominantly monolayer adsorption on homogeneous sites and kinetics consistent with a pseudo first order model.
Process simulation of green ammonia production from oil palm frond (OPF) waste via gasification: a technical feasibility study Heryadi, Rudy; Hendera, Hendera
Konversi Vol 15, No 1 (2026): APRIL 2026
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v15i1.25112

Abstract

Indonesia, as a leading palm oil producer, generates massive quantities of Oil Palm Frond (OPF) waste that are currently underutilized, especially in Kalimantan and Sumatra. This study evaluates the technical feasibility of converting OPF biomass into green ammonia as a sustainable fuel alternative. A steady-state process simulation was developed using Aspen Hysys that integrates biomass gasification, syngas cleaning, a Water-Gas Shift (WGS) unit, and a high-pressure ammonia synthesis loop. Based on a feedstock input of 16,000 kg/h, the simulation yielded an ammonia production rate of 8,381 kg/h, achieving a biomass-to-ammonia conversion ratio of approximately 1.9:1. The product purity reached 97.18 mol% (equivalent to 98–99 wt%), meeting industrial standards for commercial applications. Plant performance analysis indicated an energy conversion efficiency of 55% and a specific energy consumption of 1.03 kWh/kg NH3 across the compression and synthesis sections. These results confirm that the gasification of OPF is a technically viable pathway for green ammonia production, offering a promising solution for biomass waste management and supporting Indonesia's transition toward renewable energy.
Process intensification of silica amination through ultrasound-assisted impregnation: toward highly efficient amino-functionalized particles Ajiz, Hendrix Abdul; Widiyastuti, Widiyastuti; Setyawan, Heru; Suryandari, Ade Sonya; Erliyanti, Nove Kartika
Konversi Vol 15, No 1 (2026): APRIL 2026
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v15i1.25507

Abstract

Amine-functionalized porous silica is a highly promising material for sustainable carbon capture; however, increasing amine loading is often limited by pore blocking and diffusion resistance of the modifying agents. This study proposes an ultrasound-assisted ex-situ impregnation strategy to enhance aminopropyl grafting efficiency within macroporous silica matrices. Macroporous silica particles were synthesized via a sol-gel spray drying route using an anionic surfactant template and subsequently functionalized with alkoxy-aminopropyl ligands. The results demonstrate that the synergistic effects of ultrasonic irradiation and macroporous morphology significantly improve ligand distribution homogeneity, suppress particle agglomeration, and promote aminopropyl penetration into the internal pore network while minimizing pore blocking induced by self-condensation. FTIR and TG-DTA analyses confirm a substantial increase in aminopropyl loading up to 0.9610 mmol g-1 silica, nearly twice that achieved by conventional impregnation, despite a reduction in specific surface area due to pore filling. Overall, this approach provides an efficient and scalable pathway for producing amine-rich silica adsorbents with enhanced accessibility and strong potential for sustainable CO2 capture applications.
The effect of activated carbon on the adsorption of coconut shell liquid smoke on the coagulation process of latex clone PB 260 Achmad, Feerzet; Deviany, Deviany; Huda, Asyifa Duwiyan Nuril; Fortunatus, Hottua Ernest; Satria, Arysca Wisnu; Yuniarti, Reni; Aryani, Wika Atro; Hasyim, Ummul Habibah
Konversi Vol 15, No 1 (2026): APRIL 2026
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v15i1.25704

Abstract

This study investigated the effectiveness of coconut shell–derived liquid smoke (CLS) and activated carbon–treated liquid smoke (CLSC) as natural coagulants for natural rubber latex clone PB 260, compared with 2% formic acid (FA). Rubber quality was assessed based on Total Solid Content (TSC), Dry Rubber Content (DRC), initial plasticity (Po), Plasticity Retention Index (PRI), ash content, dirt content, volatile matter, and Mooney viscosity according to the SNI 06-1903-2017 standard for Indonesian Standard Rubber (SIR 20). Experiments were conducted using fresh latex from clone PB 260 under the D3 tapping system, with 150 mL of latex treated with each coagulant. FA produced the fastest coagulation time (3.39 min), while CLS and CLSC required 4.37 and 4.29 min, respectively. CLS showed the highest DRC (15.33%), whereas CLSC provided better rubber stability with the highest PRI (85.83%) and high Mooney viscosity. All coagulants met SIR 20 limits for ash, dirt, and volatile matter, although Po values remained below the standard.
Reframing residual sugars as value: A review on selective fermentation for ethanol and fructose co-production Zeinelabdeen, Mohammed A.; Mohammed, Adil A.; Siddig, Muzamul M. H.; Mohamad, Khalid M. O.; Kheiri, Abubakr Hassan
Konversi Vol 15, No 1 (2026): APRIL 2026
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/k.v15i1.25914

Abstract

This review examines selective fermentation as an emerging strategy for the co-production of ethanol and fructose from mixed-sugar feedstocks. Conventional fermentation processes aim to maximize ethanol yield through complete sugar conversion, thereby treating residual sugars, particularly fructose as process inefficiencies. In contrast, selective fermentation exploits the intrinsic glucophilic behavior of Saccharomyces cerevisiae, enabling preferential conversion of glucose into ethanol while preserving fructose as a high-value co-product. Date-based substrates, including low-grade fruits and processing residues, are highlighted as abundant and underutilized resources rich in glucose–fructose mixtures. The review discusses the fundamental aspects of yeast metabolism, sugar transport mechanisms, and fermentation pathways that govern substrate selectivity. In addition, the role of fructose as a versatile platform molecule for the production of bio-based chemicals is emphasized within an integrated biorefinery framework. Key operational parameters affecting selective fermentation performance, such as temperature, pH, aeration, and substrate concentration, are critically analyzed. Existing studies reveal a persistent trade-off between ethanol yield and fructose retention, particularly under high-sugar and industrial-scale conditions. Furthermore, current limitations in kinetic modeling and process optimization are identified as major barriers to industrial implementation. Selective fermentation presents a promising approach to enhance process efficiency and economic value in biomass conversion systems. Future research should focus on developing robust kinetic models, optimizing operating conditions, and integrating downstream processing to enable scalable and economically viable ethanol–fructose biorefineries.

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