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The low cost and excellent catalytic properties of lipase for industrial processes are highly desirable. A promising new approach involves the support modification of lipase and spacer arm, which enables the enhancement of lipase properties. This study investigates the immobilization of crude lipase from Mucor miehei onto a Polyurethane Foam (PUF) surface using various coating techniques. The PUF matrix was obtained through isocyanate and polyol reactions. Subsequently, the PUF was coated by adsorbing lipase and adding edible support material. The immobilized lipase was then utilized in the hydrolysis of coconut oil to produce fatty acids. Furthermore, the immobilized enzyme was employed in the esterification of fatty acids to produce bio-flavors. The results demonstrate that the attachment reaction using support material, namely lecithin, gelatin, MgCl2, and Polyethylene glycol 6000 (PEG), all of which are simple and edible, was able to enhance the stability and reusability of lipase. This immobilization technique increased triglyceride hydrolysis into FFA by 422%. The successful edible support modification of immobilized lipase from M. miehei on PUF, coupled with significantly enhanced enzyme stability and catalytic activity, offers a promising, environmentally friendly solution for diverse applications in the food industry. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

This study compared free and immobilized cells with palm oil and hexanol as an extractant in a large volume ratio of extractant to the broth. Fermentation was conducted using TYA (Tryptone-Yeast-Acetate) media, glucose as the substrate and the palm oil, hexanol, and a mixture of hexanol and palm oil with a composition of 1:1 v/v as an extractant in the fermentation with a large volume ratio of extractant to broth of 5. The strain was inoculated as free-suspended cells of C. saccharoperbutylacetonicum N1-4 and immobilized cells in calcium alginate. The best extractant results for the acetone fermentation process in the ratio of extractive fermentation of free cells and immobilized cells were using palm oil as extractants. This extractant harvested acetone well, with the acetone concentration in the extractant at 18.41 g/L in free cell fermentation and 17.07 g/L in immobilized cell fermentation. The maximum total acetone concentration was up to 93.72 g/L broth. Using palm oil as an extractant in a large extractant volume combined with immobilization is an alternative to enhance bioacetone production by effectively reducing the toxicity effect of the products and minimizing nutrient requirements.

The main challenge with membrane bioreactors is fouling, which leads to decreased flux performance and a shortened membrane lifespan. This study aims to provide a solution for the flux recovery and removal of irreversible fouling on Polyvinylidene Fluoride (PVDF) membranes without damaging their structure using sulfate radicals. Sulfate radicals are formed via peroxodisulfate precursors that are activated by Fe2+. The membrane flux recovery and irreversible fouling ratio were 88.45-99.04% and 11.60-0.96%, respectively, at operating temperatures of 298-308 K. The PVDF membrane has been tested for microfiltration and washed up to 6 times per cycle. The mechanical properties, XRD, SEM-EDX, and ATR-FTIR characterization of the PVDF membrane after washing with PDS/Fe2+ did not show a negative effect on the PVDF structure. Additionally, the results of the kinetic and thermodynamic studies showed that washing with PDS/Fe2+ inhibited the formation of fouling particles on the membrane surface. Based on this study, sulfate radical oxidants with PDS precursors activated by Fe2+ can be applied as cleaning chemicals for PVDF membranes without damaging their structures.

Subcritical water hydrolysis of bagasse requires energy to convert lignocellulosic biomass into fermentation-ready sugars. Bagasse biomass has the potential to be used as raw material for the production of reducing sugar. This study evaluates the effectiveness of the hydrolysis process using an oven and autoclave through economic and energy analysis. The variables used were hydrolysis time of 20-60 minutes, oven temperature of 110-170°C, and autoclave temperature of 120-130°C. Reduced sugar concentration was obtained from analysis using the DNS (dinitro salicylic acid) method. The results of the analysis show that time and temperature have a significant effect on the yield of reducing sugar. The highest reduced sugar concentration from subcritical water hydrolysis using an oven was 27.4 g/L at 170°C operating conditions for 60 minutes with a total cost of Rp 351,744 and energy requirement of 480 W.h. In hydrolysis using an autoclave, it was obtained at 14.7 g/L at 125°C for 40 minutes with a total cost of IDR 923,079 and energy requirements of 1,936.67. Hydrolysis using an oven is more recommended than autoclaving because it is economical and has lower energy consumption.

Membrane bioreactor (MBR) deteriorates due to fouling on the membrane pores, which can reduce the membrane performance. To reduce membrane fouling, the addition of inorganic filler can enhance the antifouling properties. This study investigates two different membrane preparation by thermally induced phase separation (TIPS) and dip coating methods to modify hollow fiber membrane with Silver Nanoparticles (AgNPs)-Zeolites used in MBR for industrial wastewater treatment. Performance was evaluated by analyzing the flux of water and wastewater, rejection, water content, and antifouling properties. Characterization result represented the synthesized silver nanoparticles had similar diffraction peak with commercial AgNPs, then the micrograph of AgNPs and zeolites addition membrane showed that the inorganic material had an octahedral shape representing zeolite crystal and irregular shape representing AgNPs. The addition of zeolites and AgNPs resulted in satisfying performance, increased flux, rejection, and antifouling properties.

The competitive reactions of lignocellulose hydrolysis and monosaccharide degradation in the subcritical water (SCW) hydrolysis of coconut husk were investigated to optimize the reducing sugar yield. Optimization analysis was performed by response surface methodology (RSM) and kinetics studies. Parameters of process optimization were varied at 130-170 °C for 15-45 min. The reducing sugars were measured using the Dinitro salicylic acid method. The sugar yield increased when the temperature increased from 130 °C to 170 °C. The highest reduction sugar yield of 4.946 g/L was obtained at 183.6 °C for 4.8 min and 23.4 liquid/solid ratio (LSR). Kinetics studies were carried out at temperature variations of 150, 170, and 190 °C and pressures of 60, 80, and 100 bar for 5 to 60 min. The yield of reducing sugar decreased with increasing temperature. The kinetic model 2B is the best method to explain the competitive reaction kinetics of coconut husk hydrolysis. This research is an innovation to increase the reducing sugar to make the process more commercially viable. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

PT. Industri Gula Glenmore (PT. IGG) setiap tahunnya memproduksi 14.300 ton abu ampas tebu (AAT) sebagai hasil samping pembakaran boiler yang belum dimanfaatkan secara maksimal. Menariknya, AAT memiliki kandungan silika tinggi yaitu 68,5% yang dapat ditingkatkan nilainya sebagai substitusi parsial semen dalam pembuatan bata beton. Oleh karena itu, pada penelitian ini komposisi dan ukuran partikel AAT dioptimalkan dalam pembuatan bata beton. Optimasi dilakukan dengan menggunakan Response Surface Methodology (RSM) untuk memahami perilaku faktor-faktor signifikan yang mempengaruhi kuat tekan bata beton. RSM ditentukan dengan menggunakan software Design-Expert V11. Bata beton dibuat dengan perbandingan semen dan pasir menggunakan perbandingan 1:6 dengan variasi AAT 5% sampai 25% dari berat normal semen. Hasil pengujian di Workshop menunjukkan bahwa penggunaan Fly Ash dan kapur sebagai bahan pengikat untuk menggantikan sebagian semen dengan variasi 23, 26, 28, 30, dan 33% menghasilkan kuat tekan berturut-turut sebesar 56, 52, 49, 40, dan 34 kg/cm2. Dengan demikian, bata beton pada penelitian ini termasuk dalam mutu tingkat 3 berdasarkan SNI 03-0349-1989. Inovasi ini merupakan solusi untuk meningkatkan nilai tambah AAT dan menjadi peluang bisnis baru bagi PT. IGG di masa depan PT. The Glenmore Sugar Industry (PT. IGG) annually produces 14,300 tons of Sugarcane Bagasse Ash (SCBA) as a by-product of boiler combustion that has not been fully utilized. Interestingly, SCBA has a high silica content of 68.5%, which can be valorized as a partial substitution of cement in the manufacture of concrete bricks. Therefore, in this study the composition and particle size of SCBA were optimized in the manufacture of concrete bricks. Optimization was carried out by using Response Surface Methodology (RSM) to understand the behavior of significant factors affecting the compressive strength of concrete bricks. RSM was determined using the Design-Expert V11 software. Concrete bricks were made with a ratio of cement and sand using a ratio of 1:6 with a variation of bagasse ash 5% to 25% of the normal weight of the cement. The test results showed that the use of fly ash and lime as a binder to replace some cement with variations of 23%, 26%, 28%, 30%, and 33% resulted in a compressive strength of 56 kg/cm2, 52 kg/cm2, 49 kg/cm2, 40 kg/cm2, and 34 kg/cm2, respectively. Thus the concrete brick in this study was included in the quality level 3 based on SNI 03-0349-1989. This innovation is a solution to increase SCBA's added value and a new business opportunity for PT. IGG in the future.

The problem of crude oil reserve shortage and air quality decline currently have led researches on renewable fuel such as bioethanol and biohydrogen. The attempt to provide such biofuel involves the utilization of enormously available wasted materials, lignocellulose. Coconut husk is one of such materials available in Indonesia. The previous work had reported the quantity of total reducing sugar produced after the enzymatic hydrolysis of pretreated coconut husk. The pretreatment methods used were dilute sodium hydroxide solution (1 and 4% w/v), 1,3-methylmethylimidazolium dimethyl phosphate ionic liquid and the combination of both methods. This work focused on constructing the mathematical model which describes the kinetic of those enzymatic hydrolysis reactions. Mathematical model expressions help describing as well as predicting the process behavior, which is commonly needed in the process design and control. The development of mathematical model in this work was done based on the total reducing sugar concentration resulted in batch hydrolysis reaction. The kinetic parameters including initial available substrate (S0), maximum reaction rate (rmax), and half-maximum rate constant (KM). According to the values of half-maximum rate constant (KM), the enzymatic hydrolysis performance of coconut husk treated using ionic liquid is better than that treated using dilute alkaline solution as the former had shown lower KM value and hence higher enzyme affinity to the substrate. The best hydrolysis result was performed using combination of 1% dilute sodium hydroxide solution and ionic liquid with kinetic model parameter of 0.5524 g/L.h of rmax, 0.0409 g/L of KM, and 4.1919 g/L of S0. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Preventing the further degradation of monomeric or oligomeric sugar into by-product during biomass conversion is one of the challenges for fermentable sugar production. In this study, the performance of subcritical water (SCW) and enzymatic hydrolysis of coconut husk toward reducing sugar production was investigated using a severity factor (SF) approach. Furthermore, the optimal condition of SCW was optimized using response surface methodology (RSM), where the composition changes of lignocellulose and sugar yield as responses. From the results, at low SF of SCW, sugar yield escalated as increasing SF value. In the enzymatic hydrolysis process, the effect of SCW pressure is a significant factor enhancing sugar yield. A maximum total sugar yield was attained on the mild SF condition of 2.86. From this work, it was known that the SF approach is sufficient parameter to evaluate the SCW and enzymatic hydrolysis of coconut husk. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Coconut husk (CCH) as an abundant agricultural waste in Indonesia has the potential to be utilized for sugar production, which is the intermediate product of biofuel. In this study, subcritical water (SCW) assisted by nitrogen (N2) was developed to enhance the enzymatic hydrolysis of CCH. SCW process was optimized by varying the operation condition: the pressure of 60-100 bar, the temperature of 150-190 °C, and the time of 20-60 min. The SCW-treated solid was subsequently hydrolyzed by utilizing a mixture of commercial cellulase and xylanase enzymes. The result shows that the optimum total sugar yield was obtained under the mild condition of SCW treatment, resulting in the sugar of 15.67 % and 10.31 % gained after SCW and enzymatic hydrolysis process, respectively. SEM and FTIR analysis of SCW-treated solid exhibited the deformation of lignin and solubilization of cellulose and hemicellulose, while XRD and TGA revealed an increase of the amount of crystalline part in the solid residue. The use of N2 in SCW treatment combined with enzymatic hydrolysis in this study suggested that the method can be considered economically for biofuel production from CCH waste in commercial scale. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Bio‐based fatty acids (FAs) produced through hydrolysis of natural oils and fats are promising chemical feedstocks for increasing the economic value of renewable raw materials. In this work, lecithin, gelatin, PEG, and MgCl2 were employed as the co-immobilized material of crude lipase Mucor miehei immobilization on the polyurethane foam (PUF) matrix for hydrolysis of coconut oil to Free Fatty Acid (FFA). The unconventional immobilized technique was used through cross-linking and covalent bond. Single factor analysis and response surface method were utilized to determine the optimum conditions of the hydrolysis reaction. After optimization, co-immobilized lipase was examined for storage stability at a temperature of 4°C and reusability performance. The optimum conditions for coconut oil hydrolysis were obtained on the co-immobilized-PUF ratio, water-oil ratio, and reaction time of 20.17 w/w, 4.45 w/w, and 20 h, respectively. Under these conditions, the acid value as lauric acid enhanced 573% to 3.21 mg KOH/g oil. Storage stability attained through remaining activity on free lipase, PUF-lipase, PUF-co-immobilized-lipase were 9.89%, 42.3%, and 91.88%, respectively. In this study, the application of PUF-co-immobilized lipase in hydrolysis reactions can be reused up to 5 times. Characteristics of the addition of co-immobilized lipase have been analyzed using Fourier Transform Infra Red (FTIR) and Scanning Electron Microscope (SEM), showing the presence of functional groups binding and the changes in the surface matrix structure.

Recently, edible oil has been employed for biodiesel feedstocks. However, the use of such oil to fulfil energy demand raises certain problems, such as the sustainability of the practice due to its competition with food. Therefore, it is necessary to obtain alternative resources from non-edible oil. One promising biodiesel feedstock from a non-edible oil source is crude Calophyllum inophyllum oil (CCIO) because of its high oil content. The highest oil content in CCIO is triglyceride (TG), which influences biodiesel production. The higher content of TG results in a higher yield of biodiesel. Previous research on the conversion of CCIO into biodiesel with an environmentally friendly purification method and fast separation of compounds is limited. In this work, batchwise solvent extraction (BSE) and microwave-assisted extraction (MAE) were compared to achieve an effective and efficient method for TG purification. By using the microwave method with 450 watts of power for 30 minutes, a high content of TG was obtained. It was found that TG content increased significantly, from 75.99% to 83.46%. Using the BSE method with a mixture of petroleum ether?methanol (methanol 25%), a solvent-to-oil mass ratio of 5:1, time for the first 2 stages (48 hours), the TG content obtained was 82.02%. The data obtained for the microwave method are almost equivalent to the first 2 stages of BSE with regard to TG content (83.46% compared to 82.02%) and almost 0.01 times shorter than BSE (30 minutes compared to 48 hours).

Cellulase and xylanase were covalently immobilized on chitosan magnetic particles. They were employed as catalysts to produce reducing sugar from coconut husk individually and simultaneously. Fourier Transform Infrared Spectroscopy (FT-IR) and Bradford’s protein analysis confirmed that the enzymes were covalently immobilized on the support. Cellulase from Aspergillus niger and Trichoderma reesei immobilized on chitosan magnetic microparticles yielded 0.352 g/L and 0.316 g/L of reducing sugar respectively, while immobilized xylanase from Trichoderma longibachterium yielded 0.432 g/L. The simultaneous use of cellulase and xylanase produced 0.8034 g/L of sugar, and the addition of glutaraldehyde as a cross-linking agent increased the amount of reducing sugar. Enzyme could maintain its activity at 91% for up to five cycles. Using nanosized particles resulted in a sugar yield of 0.49 g/l and 54.7 % of its activity maintained after five cycles.

The effectivity of employing two types of cellulases from Aspergillus niger and Trichoderma resei covalently immobilized on chitosan microparticle was investigated. Reducing sugar from CMC yielded by immobilized cellulase from T. resei alone and A. niger alone was 0.316 g/L and 0.244 g/L, respectively. Simultaneous use of both cellulases shows a significant increase of reducing sugar produced to 1.020 g/L. The effective combination of this two types of cellulases also occurred when coconut husk was used as substrate. A very high enzyme coupling of 92.06% compared to free enzyme was obtained in the immobilization. Addition of GDA not only increased enzyme coupling to 100% but also improved sugar produced. Immobilized cellulase was successfully maintained its activity until 5 cycles

Objectives: To investigate the proximate composition, mineral content, and phytochemical compounds in Calophyllum inophyllum (C. inophyllum) leaves. Moreover, isolation and identification of pyrene were also performed. Methods: C. inophyllum leaves were extracted with methanol by percolation methods. The proximate composition of C. inophyllum leaves was analyzed by standard methods. Mineral contents in this plant were analyzed by using atomic absorption spectrophotometer. Phytochemical screening and analysis of this plant were performed by spectrophotometric method. Washing method with carbon disulfide was used for isolating dihydropyrene compound from C. inophyllum leaves extracts. Results: The result revealed that C. inophyllum leaves contained 11.24% moisture, 4.75% ash, 6.43% crude protein, 23.96% crude fiber, 9.91% carbohydrate, and energy (79.17 kcal/100 g). The leaves also contained 0.007% iron, 1.240% calcium, 0.075% sodium, 0.195% magnesium, 0.100% ppm potassium, and 0.040% phosphorus. Moreover, 11.51% alkaloid, 2.48% triterpenoid, 2.37% flavonoid, 7.68% tannin, 2.16% saponin, 2.53% polyphenol, were identified in the methanolic crude extracts of C. inophyllum leaves. It was found that trans-2-[2-(trifluoromethyl)phenyl]-10b,10c-dimethyl-10b,10c-dihydropyrene was obtained at purity of 79.18% (22.17% yield) from C. inophyllum leaves. Conclusions: C. inophyllum leaves may be used as a good source of fiber. It was found that C. inophyllum leaves have the potential as herbal drugs due to their phytochemical content. The separation, isolation, and purification of bioactive compounds from this methanolic crude extract and their biological activity are under further investigation.

The highest population of Calophyllum inophyllum is in Indonesia. One of the bioactive compound contained in C. inophyllum leave is cholestane. The extraction method was employed to obtain crude extract from these leaves. It was followed by identification of the bioactive compounds. The purpose of this research was to develop a process for isolating and identifying cholestane and dihydropyrene from methanolic extract of C. inophyllum leaves in high yield and purity. The effect of crude extract to non-polar solvent mass ratio and non-polar solvent types on the separation of the bioactive compounds were also systematically investigated. New compounds (trans-2-[2-(trifluoromethyl)phenyl]-10b,10c-dimethyl-10b, 10c-dihydropyrene and anti-4-aza-B-homo-5.alpha-cholestane-3-one) were also identified in C. inophyllum leaves. The successful separation was obtained by employing CS2 as the solvent and crude extract to CS2 mass ratio of 1/10 (g/g).

This study concern sugars hydrolyzed from the high-lignin coconut coir dust using moderate subcritical water (SCW) hydrolysis at pressures 20-40 bar for 1 h and to evaluate the consumable costs driver generated. The SCW method produced two products, sugar liquid and solid (SCW-treated substrate). The solid was proceeded to prepare the sugar via enzymatic hydrolysis using pure cellulase. Yield of sugar hydrolyzed from lignocellulose by SCW technique was 0.25 gram sugar/gram cellulose +hemicellulose, or 0.09-gram sugar/gram lignocellulose at 160 °C and 40 bar. While, the maximum yield of sugar liberated enzymatically from SCW-treated solid was 0.35-gram sugar/gram cellulose+hemicellulose, or 0.13-gram sugar/gram SCW-treated solid. It was found that carbon dioxide gas was the highest cost driving in SCW hydrolysis.

Sugarcane bagasse is one of lignocellulose materials that can be converted to biofuel. This work was aimed to develop new pretreatment combination methods to process sugarcane bagasse lignocellulose into biofuel (bio-hydrogen). Pretreatment of sugarcane bagasse using NaOH solution in combination with ionic liquid [DMIM]DMP enhanced the enzymatic hydrolysis significantly. After the pretreat-ment, the content of cellulose and hemicellulose increased by 29.31% compared to the untreated one. Cellulose and hemicelluloses were used as raw materials to produce reducing sugars, that can be con-verted to bio-hydrogen via fermentation. After being subjected to combined pretreatment processes, the crystalline index of sugarcane bagasse decreased significantly compared to solely NaOH pretratment. This indicates a more amorphous structure of the sugarcane bagasse, which makes it is easier to be hy-drolyzed into reducing sugars. The recovery of cellulose + hemicellulose after pretreatment for 20 min and 120 °C was 92%, and the yield obtained was 0.556 g sugars/g (cellulose + hemicellulose) after 12 h and the bio-hydrogen yield was 0.46 mol H2/mol sugars consumed after 48 h fermentation. The use of recycled of ionic liquid showed similar performance compared to the use of fresh ionic liquid. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

This study aims to produce reducing sugar hydrolyzed from substrate, coconut coir dust pretreated by recycled ionic liquid and its combination with alkaline. The 1H NMR and FTIR were performed to ver-ify the synthesized ionic liquid methylmethylimidazolium dimethyl phosphate ([mmim][dmp]). The structure of pretreated substrates was analyzed by XRD measurement. The used ionic liquid was recy-cled twice to re-employ for substrate pretreatment. The treated- and untreated-coconut coir dust were hydrolyzed into sugars using pure cellulase. The reaction, which called an enzymatic hydrolysis, was conducted at 60 °C, pH 3, for 48 h. The yields of sugar hydrolyzed from fresh IL-pretreated, 1R*IL-pretreated and 2R*IL-pretreated substrates were of 0.19, 0.15 and 0.15 g sugar / g cellu-lose+hemicellulose, respectively. Pretreatment with NaOH or the combination of NaOH+IL resulted in yields of reducing sugars of 0.25, 0.28 g/g, respectively. When alkaline combined with the recycled ionic liquids, NaOH+1R*IL, NaOH+2R*IL in the pretreatment, the yields of sugar were relatively similar to those obtained using alkaline followed by fresh ionic liquid. If the mixture enzymes, cellu-lase+xylanase, used to liberate sugars from fresh IL-pretreated, or recycled IL-pretreated substrates, the amount of sugar (concentration or yield) increased slightly compared to that employing a single cel-lulase. These findings showed that recycled IL pretreatment of the high-lignin lignocellulose, coconut coir dust, is a new prospect for the economical manufacture of fermentable sugars and biofuel in the coming years. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

Electrochemical synthesis of hydroxyapatite particles was performed from a homogeneous solution of Na2H2EDTA.2H2O, KH2PO4 and CaCl2 without stirring to investigate the mechanism of hydroxyapa-tite formation. We found that OH- ions generated by water reduction at the cathode play an important role in the formation of hydroxyapatite particles. The OH- ions induce the liberation of Ca2+ ions and the dissociation of phosphoric acid, which serve as the reactants for the formation of hydroxyapatite particles. Two layers with a clear boundary were formed during electrolysis. The upper layer comprises the produced particles and the lower layer is a homogeneous solution. The produced particles were held in the region between the electrodes mainly due to the electrostatic interactions of charged particles in an electric field. The hydroxyapatite particles are agglomerates consisting of spherical particles. Aging the suspension for 24 h after electrolysis leads to the transformation of hydroxyapatite to brushite. Thus, if producing hydroxyapatite is desired, the particles should be continuously removed from the system. This method appears to be promising as a continuous process to produce hydroxyapatite parti-cles using an electrochemical method. © 2014 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

Hexamethylene Tetramine (HMTA) atau yang lebih dikenal dengan hexamine memiliki penggunaan yang luas di bidang industri kimia yaitu sebagai akselerator pada industri karet, campuran TNT pada industri bahan peledak, shrink-proofing agent untuk memperindah warna pada industri tekstil, bahan pelapis butiran pupuk urea, inhibitor korosi, curing agent pada industri resin, bahan baku antiseptik, serta industri serat selulosa. Selain itu, dalam jumlah rendah, hexamine juga digunakan pada sintesis glycine maupun sebagai stabilizer pada polyvinyl acetate dan pelarut pada ekstraksi fenol. Indonesia sendiri hanya memiliki dua industri untuk memproduksi hexamine dan belum cukup untuk memenuhi kebutuhan sehingga Indonesia masih harus impor. Padahal kebutuhan hexamine terus meningkat dari tahun ketahun. Menurut BPS (2004 - 2011), impor hexamine Indonesia pada tahun 2011 mencapai 13.227.201 kg. Melihat banyaknya kegunaan hexamine dalam berbagai bidang dan perkembangan industri di Indonesia yang memanfaatkan produk ini sebagai bahan baku, maka pendirian pabrik ini sangat dibutuhkan. Pabrik Hexamethylene Tetramine direncanakan berdiri pada tahun 2019 yang berlokasi di Palembang, Sumatera Selatan dengan kapasitas produksi sebesar 7000 ton/tahun. Proses yang digunakan pada perencanaan Pabrik Hexamethylene Tetramine ini adalah menggunakan proses Meissner. Proses pembuatan hexamine dengan proses ini dapat dibagi dalam beberapa tahap, antara lain tahap persiapan bahan baku yakni ammonia dan formaldehid, tahap pembentukan hexamine di dalam reaktor yang selanjutnya diproses lebih lanjut untuk memisahkan kristal hexamine yang telah terbentuk, dan tahap pemurnian dan penyimpanan produk. Pabrik Hexamethylene Tetramine ini direncanakan beroperasi secara kontinyu selama 24 jam dengan waktu produksi 330 hari/tahun. Berdasarkan analisa ekonomi yang telah dilakukan diperoleh internal rate of return sebesar 19,05 % dengan pay out time selama 4,9 tahun dan break even point sebesar 40%. Ditinjau dari uraian di atas, maka secara teknis dan ekonomis, pabrik Hexamethylene Tetramine dari ammonia dan formaldehid layak untuk didirikan. Kata Kunci—Hexamethylene Tetramine, ammonia, formaldehid, Meissner

Etanol merupakan salah satu bahan kimia yang memiliki peranan penting dalam kehidupan manusia misalnya digunakan sebagai bahan baku industri turunan alkohol. Akan tetapi etanol yang dapat dimanfaatkan sebagai campuran bahan bakar harus mempunyai grade sebesar 99,5-100% volume, grade tersebut mutlak karena jika berkadar di bawah 90%, mesin tidak dapat menyala karena kandungan airnya terlampau tinggi. Bioetanol dengan kadar kemurnian 95% masih layak dimanfaatkan sebagai bahan bakar motor. Hanya saja, dengan kadar kemurnian itu perlu penambahan zat antikorosif pada tangki bahan bakar agar tidak menimbulkan karat. Salah satu bahan baku yang dimanfaatkan untuk produksi bioetanol adalah sorghum karena memiliki kadar glukosa yang cukup tinggi. Bioetanol dapat diperoleh dengan proses fermentasi yang melibatkan mikroorganisme. Pra desain pabrik bioetanol dari batang sorghum ini menggunakan proses fermentasi. Batang sorghum digiling dalam roll mill dan ditambahkan air sehingga menghasilkan nira. Adapun mikroorganisme yang digunakan adalah Saccharomyces cereviceae. Bakteri ini mampu mengurai gula tanpa kehadiran oksigen dan menghasilkan etanol dan karbondioksida. Konsumsi premium pada 2017 diperkirakan sebesar 63.052.915 kL/tahun. Proses pembuatan bioetanol ini berlangsung secara kontinyu, 24 jam/hari dan 330 hari/tahun dengan perencanaan sebagai berikut, Kapasitas produksi : 355.916,41 kL/tahun, Bahan baku : 5.000.000 ton/tahun. Pabrik bioetanol ini akan didirikan di Sukoharjo pada tahun 2017. Berdasarkan analisa ekonomi yang dilakukan, diperoleh hasil sebagai berikut: Internal Rate of Return : 36 % per tahun, Pay Out Time : 4.09 tahun, dan BEP : 25.13 %.

Increasing the Performance of Enzymatic Hydrolysis of Rice Straw Using Mixed Crude Cellulases fromTrichoderma reesei and Aspergillus niger. The objective of this work is to compare the effectiveness of mixed crudeenzyme cellulase from T. reesei and A. niger with commercial enzyme from A. niger, and to investigate effect ofenzyme to substrate ratio to performance of enzymatic hydrolysis of rice straw. The commercial enzyme from FlukaBiochemica was used, and crude enzyme were prepared by solid fermentation with simple media. Before hydrolized,the rice straw was grinded and sieved and then heated at 85 oC with 2% sodium hydroxide for six hours. Hydrolysis wasconducted in 300 mL beaker flask equipped with mechanical stirrer. Samples were analyzed by dinitrosalicylic acidmethod and measured by spectrophotometer. Both of commercial and mixed crude enzyme show that, the higherenzyme to substrate ratio was higher the glucose concentration obtained. However, ratio of glucose obtained to enzymeused become smaller. The mixture of crude enzyme from T. reesesi dan A. niger that produced in this work was twofold more effective to hydrolyze rice straw than using cellulase enzyme of A. niger from Fluka Biochemika

Membrane bioreactors for wastewater treatment research have been carried out. In this system, membrane replaces the function of the sedimentation tank. Until recent time, fouling was still the main problem for membrane processes. This research has investigated the effect of MLSS concentration and back flushing on external membrane bioreactor performances such as COD and BOD reduction, and the back flushing effect for domestic wastewater treatment. Polyacrylonitril hollow fiber membrane with pore diameter 0.1-0.01 m, surface area 0.075 m2 was used in this research. This process was at HRT 5 hour, no sludge disposal, intermittent operation, and permeate exiting from membrane shell side. Optimum condition was obtained at a transmembrane pressure (TMP) of 1.45 bar. Back flushing was conducted for 10 minute at 3.0 bar pressure. Effective back flushing was shown after operation at MLSS of 7500 and 10000 mg/l. The result of this research shows that COD and BOD in the domestic wastewater decreased almost 98%. MLSS and MLVSS degradations were 98.6% and 98%, respectively.

Indonesia merupakan negara agraris yang menghasilkan beragam hasil pertanian yang melimpah. Salah satu hasil pertanian yang menonjol di Indonesia adalah kelapa. Produksi buah kelapa di Indonesia rata-rata sebanyak 15,5 miliar butir/tahun atau setara dengan 3,02 juta ton kopra, 3,75 juta ton air, 0,75 juta ton arang tempurung, 1,8 juta ton serat sabut (coir fiber) dan 3,3 juta ton debu sabut (coir dust/ cocopeat. Komposisi sabut kelapa terdiri dari 25% gabus dan 75% serat . Tetapi, debu sabut kelapa masih dikembangkan sebatas sebagai media tanam. sisanya akan menjadi limbah dengan kontribusi sangat besar dari pengisi pada volume total sampah domestiK. Banyaknya komoditas kelapa dan potensi limbah sabut yang dihasilkan, membuat pemanfaatan Debu Sabut menjadi bahan yang bernilai ekonomis patut untuk dilakukan. Salah satunya adalah sebagai bahan pembuatan Surfakatan Sodium Ligno Sulfonat (SLS) yang selama ini komoditasnya diperoleh seluruhnya dari impor. Adapun tahapan proses pembuatan SLS dari Debu Sabut kelapa adalah mempersiapan Bahan Baku berupa Debu Sabut Kelapa. Dilanjutkan dengan pemasakan/pulping menggunakan metode organosolv dengan alat pemasak digester (R-120). Dari lindi hitam yang dihasilkan, akan diproses dengan Isolasi Lignin dengan metode presipitasi asam. Lindi hitam yang telah didapat diendapkan dengan menambahkan secara perlahan H2SO4dengan konsentrasi 20% sampai pH 2 pada tangki isolasi pertama (M-211).Proses isolasi dengan metode pengasaman banyak digunakan untuk mendapatkan lignin dengan kemurnian tinggi. Untuk Menghasilkan SLS, Lignin Isolat perlu direaksikan dengan bahan penyulfonasi natrium bisulfit (NaHSO3), sehingga menghasilkan natrium lignosulfonat (SLS) pada reaktor sulfonasi (R-310). Berlokasi di Provinsi Riau, Pabrik ini akan dibangun dengan kapasistas 20.150 ton/tahun. Dari analisa ekonomi, diperlukan Modal tetap (FCI) sebesar Rp 316.323.349.677; Modal kerja (WCI) sebesar Rp 74.429.023.453; Investasi total (TCI) sebesar Rp 390,752,373,130 ; Biaya Produksi pertahun (TPC) sebesar Rp 1.772.425.308.777. Nilai Internal Rate of Return sebesar 53%, dimana Pay out Time akan dibayarkan selama 5 tahun. Hasil Break Event Point diperoleh 55 %.

Sorbitol yang dikenal juga sebagai glusitol, adalah suatu gula alkohol yang dimetabolisme lambat di dalam tubuh. Sorbitol banyak digunakan sebagai bahan baku untuk industri barang konsumsi dan makanan seperti pasta gigi, permen, kosmetika, farmasi, vitamin C, termasuk industri tekstil dan kulit. Pembuatan sorbitol dari bahan baku tepung tapioka. Pabrik sorbitol ini direncanakan akan didirikan di Propinsi Jawa Tengah tepatnya di Kabupaten Batang dengan kapasitas produksi 30.000 ton/tahun. Proses produksi Sorbitol menggunakan proses hidrogenasi katalitik. Pembuatan sorbitol dari bahan baku pati melalui dua tahap proses utama yaitu proses perubahan starch menjadi glukosa melalui hidrolisa double enzym. Enzim yang digunakan yaitu α-amylase dan glukoamylase. Proses hidrogenasi katalitik dilakukan dengan mereaksikan larutan dekstrose dan gas hidrogen bertekanan tinggi dengan menambahkan katalis nikel dalam reaktor (Reaktor Hidrogenasi). Gas hidrogen masuk dari bawah reaktor secara bubbling dan larutan dekstrose diumpankan dari atas reaktor sehingga kontak yang terjadi semakin baik. Sorbitol yang di hasilkan dalam pradesain pabrik sorbitol ini dengan konsentrasi 58,2%. Pendirian pabrik sorbitol memerlukan biaya investasi modal tetap (fixed capital) sebesar Rp 168.801.192.952, modal kerja (working capital) Rp 29.788.445.815, investasi total Rp 198.589.638.767, Biaya produksi per tahun Rp 368.832.813.809 dan hasil penjualan per tahun Rp 540.000.078.750. Dari analisa ekonomi didapatkan BEP sebesar 26,32%. ROI sesudah pajak 48,5 %, POT sesudah pajak 2,14 tahun. Dari segi teknis dan ekonomis, pabrik ini layak untuk didirikan.