Uji Daya Hambat Senyawa Xylitol dari Limbah Tongkol Jagung pada Bakteri Streptococcus Mutans

Corncob contains xylan content of 12.4 - 12.9% which can be converted to xylitol [1]. Xylitol significantly reduces the population of Streptococcus mutans (S. mutans) in saliva compared with fluoride [3]. The effectiveness of xylitol from corn cobs waste is an antibacterial substance of S. mutans in safe and water-soluble mouthwash. The purpose of this research is to produce xylitol from corn cobs waste and to test the xylitol inhibition as anti bacterial in S. mutans bacteria. The xylitol extraction method of corncob using aqueous sulfuric acid is 0.25; 0.5; 0.75 and 1.0%. The extraction time was then varied from 15, 30, 45, 60, 75 and 90 min. The results showed xylitol compound from corn tuna waste was highest at 0.25% sulfuric acid concentration with 30 minutes hydrolysis time of 249.7 ppm and the lowest at 0.75% acid concentration and hydrolysis time of 90 minutes is 5.6 ppm. Xylitol compounds can be obtained from corn cobs waste has the value of inhibitory growth of S. Mutans bacteria in all variations of acid concentration (H2SO4) and hydrolysis time is 100%.

PERBANDINGAN YIELD NERACA MASSA HASIL PRETREATMENT TIGA JENIS LIMBAH LIGNOSELULOSA DALAM MEMPRODUKSI POLISAKARIDA MENGGUNAKAN TEKNIK KIMIAWI

PERBANDINGAN YIELD NERACA MASSA HASIL PRETREATMENT TIGA JENIS LIMBAH LIGNOSELULOSA DALAM MEMPRODUKSI POLISAKARIDA MENGGUNAKAN TEKNIK KIMIAWI ABSTRAKLimbah lignoselulosa merupakan jenis limbah yang mengandung lignin, selulosa dan hemiselulosa (xilan). Pada lignoselulosa, senyawa yang dapat dimanfaatkan adalah hemiselulosa dan selulosa, sedangkan lignin dihilangkan. Hemiselulosa dan selulosa sebagai polisakarida dapat digunakan sebagai substrat dalam produksi enzim maupun hidrolisis secara kimia, proses tersebut dilakukan untuk mendapatkan gula yang lebih sederhana. Penelitian sebelumnya telah dilakukan ekstraksi xilan dari ampas tebu, hasil samping dari ekstraksi tersebut adalah selulosa. Oleh karena itu, penelitian ini telah membandingkan hasil ekstraksi xilan dan selulosa dalam satu jenis limbah dan membandingkan hasil keduanya diantara 3 jenis limbah lignoselulosa menggunakan metode yang sama. Penelitian ini bertujuan untuk mengekstraksi polisakarida xilan dan selulosa yang terkandung di dalam limbah ampas tebu, tongkol jagung dan jerami padi. Metode penelitian yang digunakan adalah pretreatment secara kimiawi yakni delignifikasi dengan 1 % NaOCl (v/v), ekstraksi xilan dan selulosa dengan metode alkali menggunakan 15 % NaOH pekat dan purifikasi xilan dengan 4% NaOH (v/v). Adapun target yang telah dicapai adalah perolehan polisakarida terbanyak akan digunakan sebagai bahan utama untuk memproduksi enzim. Hasil perolehan yield pada masing-masing neraca massa menunjukkan bahwa, jumlah rendemen xilan terbanyak yaitu jerami sebanyak 110 g dengan penurunan massa dari proses sebelumnya sebesar 61,5%, sedangkan untuk rendemen selulosa diperoleh juga oleh jerami yaitu sebanyak 330 g dengan penurunan massa dari proses sebelumnya sebesar 39,5% . Hal tersebut menunjukkan bahwa jumlah terbanyak pada rendemen xilan berbanding lurus dengan jumlah selulosa. Kesimpulan tersebut di perkuat dengan hasil pada dua jenis limbah lainnya, yakni berbanding lurus. Perolehan rendemen hasil purifikasi terbanyak yaitu ampas tebu (bagas) sebesar 86 gr dengan persentase penurunan massa hanya sebesar 14%.Kata kunci: Lignoselulosa, Delignifikasi, Ekstraksi, Xilan, Selulosa. COMPARISON OF YIELD BALANCE MASS RESULT OF PRETREATMENTT THREE TYPES OF LIGNOSELULOSA WASTE IN PRODUCING POLYSACCHARIDE USING CHEMICAL ENGINEERINGABSTRACTLignocellulosic waste is a type of waste containing lignin, cellulose and hemicellulose (xylan). In lignocellulose, the compounds that can be utilized are hemicellulose and cellulose, whereas lignin is removed. Hemicellulose and cellulose as polysaccharides can be used as substrates in the production of enzymes and hydrolysis chemically, the process is carried out to obtain simpler sugars. In a previous research, the extraction of xylan from bagasse, a by-product of the extraction, was cellulose. Therefore, this research compared the results of xylan and cellulose extraction in one type of waste and compare the results of the two between 3 types of lignocellulosic waste using the same method. This research aims to extract polysaccharide xylan and cellulose contained in waste bagasse, corn cob and rice straw. The research method used was chemical pretreatment ie delignification with 1% NaOCl (v/v), xylan extraction and cellulose by alkali method using 15% concentrated NaOH and purification of xylan with 4% NaOH (v/v). The target to be achieved is the acquisition of the most polysaccharides will be used as the main ingredient for producing enzymes. The yield of mass balance shows that the highest amount of xylan content is 110 g with the mass decrease from the previous process of 61.5%, while for cellulose rendemen is also obtained by straw as much as 330 g with the decrease of mass from process previously amounted to 39.5%. This shows that the largest amount of xylan content is proportional to the amount of cellulose. The conclusions are reinforced with the results of two other types of waste, which are directly proportional. The highest yield of purification result is bagasse equal to 86 gr with percentage of mass decrease only 14%.Keywords: Lignocellulose, Delignification, Extraction, Xylan, Cellulose.

Hardwood kraft pulp structural features affecting refinability

Two industrial bleached Eucalyptus globulus kraft pulps (pulps A and B), cooked from the same wood stock with slightly different alkali charges and temperatures, showed different refinability in the laboratory beating of pulp using a PFI mill. The easy to refine pulp (A) and the difficult to refine pulp (B) did not reveal significant differences in their biometric data and general chemical composition, but pulp A showed ca. 5%–10% higher mechanical strength and twice as high refinability compared to pulp B. These differences were ascribed to slightly higher intrinsic viscosity and higher xylan content of pulp A compared to pulp B (1010 vs. 860 cm3 g−1 and 20.1 vs. 17.8%, respectively). The xylan structure and its location in fiber cells were also different, which affected the pulp’s refinability. The presence of high proportion of xylan in the bulk of fibers, rather than in their outer layers, seems to favor the pulp beating. An interpretation was also proposed, according to which the aggregation of cellulose fibrils during cooking, i.e. a partial coalescence of fibril crystallites, may also have a negative effect on pulp refinability.

Comparison of pulp species in IONCELL-P: selective hemicellulose extraction method with ionic liquids

In our recent studies, it was demonstrated that the IONCELL-P process selectively dissolves hemicelluloses from bleached birch kraft pulp in a mixture of 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) and water as a solvent system. The IONCELL-P method refines paper-grade pulp to dissolving pulp with <5% hemicelluloses and allows isolation of polymeric xylan without yield losses or polymer degradation. This paper is a comparative study where paper-grade pine, birch, and eucalyptus pulps are subjected to the IONCELL-P process with two [emim]-based ionic liquids (ILs), i.e. [emim]acetate and [emim]dimethylphosphate. Also, the effect of an endoglucanase pretreatment was investigated to check whether 1) the pulp viscosity could be adjusted for the following process steps before the hemicellulose extraction and 2) the decreasing pulp viscosity would open the fiber structure and thus enhance the extraction. Under optimum conditions, the birch xylan content could be reduced from 25.4% down to 1.3% and for eucalyptus from 16.6% to 2.4%. Pine pulp xylan and glucomannan were decreased from 8.1% and 7.1% to 0.9% and 2.2%, respectively. The residual hemicellulose contents of the pine pulp could be further decreased with a hemicellulase pretreatment. The selectivity of the dissolution towards hemicelluloses was better for hardwoods. Adjusting the pulp viscosity by endoglucanase prior to the IONCELL-P process reduced the selectivity as short-chain cellulose molecules were extracted along with the hemicelluloses.

Effect of hydroxide and sulfite ion concentration in alkaline sulfite anthraquinone (ASA) pulping – a comparative study

Pulp and black liquor produced by alkaline sulfite anthraquinone (ASA) process were comprehensively characterized to evaluate the effects of ion concentration on the delignification and polysaccharide preservation. Scots pine wood meal was pulped at 160°C with a sulfite-to-hydroxide ion ratio of 0.75 and liquor-to-wood ratio of 200:1. Two concentration levels were studied in presence and absence of anthraquinone (AQ). Contrary to the expectations, already the lower concentration level (L-ASA) revealed rapid delignification in presence of AQ, while only moderate acceleration was obtained at the high concentration level (H-ASA). However, H-ASA liquor resulted in a slightly higher pulp yield of 1–2% (based on wood) but only in case of pulps with kappa numbers (KN) above 60. With progressing delignification, the yield advantage was gradually lost. The higher pulp yield at H-ASA conditions was mainly due to improved galactoglucomannan retention, which was around 2% on KN60 pulp and around 0.5% after prolonged delignification. The xylan content, on the other hand, was found to be 1% (based on wood) lower under H-ASA conditions compared to L-ASA conditions, which may be attributed to an increased solubility of short-chain polysaccharides at high alkali concentration.

Co-cooking nonwoods with hardwoods

Agricultural residues and energy crops are promising resources that can be utilized in the pulp and paper industry. This study examines the potential of co-cooking nonwood materials with hardwoods as means to incorporate nonwood material into a paper furnish. Specifically, miscanthus, switchgrass, and corn stover were substituted for poplar hardwood chips in the amounts of 10 wt %, 20 wt %, and 30 wt %, and the blends were subjected to kraft pulping experiments. The pulps were then bleached with an OD(EP)D sequence and then refined and formed into handsheets to characterize their physical properties. Surprisingly, all three co-cooked pulps showed improved strength properties (up to 35%). Sugar measurement of the pulps by high-performance liquid chromatography suggested that the strength increase correlated with enriched xylan content.