RESUMO
The application of ligninolytic bacteria and enzymes is a green pre-treatment alternative in the production of paper and biofuel from oil palm residues. In this study we investigated the ability of Lysinibacillus pakistanensis isolated from termite gut in degrading the lignin component of oil palm residues. The residues were biotreated with the bacterial strain in an aerated submerged fermentation system for 7 days at 30 , pH 7 and compared with untreated control. Enzyme activities were determined using specific substrates. Peak lignin peroxidase (377.6 U/L), manganese peroxidase (218.19 U/L), and laccase (405.4 U/L) activity were recorded after 4,4, and 5 days of incubation respectively, using oil palm leaf as substrates. Lignin loss of 4.5%, 5.7% and 6.6% in oil palm leaf, oil palm trunk and empty fruit bunch respectively was achieved after treatment with the microorganism. SEM images revealed structural changes in the cell wall of the residues. Pre-treatment with this bacterial strain has promising prospects of improving the efficiency of the pulping process in an environmentally safe manner.
A aplicação de bactérias e enzimas ligninolíticas é uma alternativa verde de pré-tratamento na produção de papel e biocombustível a partir de resíduos de óleo de palma. Neste estudo, investigamos a capacidade de Lysinibacillus pakistanensis isolado do intestino de cupins na degradação do componente de lignina dos resíduos de dendê. Os resíduos foram biotratados com a estirpe bacteriana num sistema de fermentação submersa arejado durante 7 dias a 30ºC, pH 7 e comparados com controle não tratado. As atividades enzimáticas foram determinadas usando substratos específicos. Pico de lignina peroxidase (377,6 U/L), peroxidase de manganês (218,19 U/L) e atividade de lacase (405,4 U/L) foram registradas após 4,4 e 5 dias de incubação, respectivamente, utilizando como substratos a folha da palmeira de dendê. A perda de lignina de 4,5%, 5,7% e 6,6% na folha da palmeira, no tronco do dendezeiro e cacho de frutas vazio, respectivamente, foi alcançada após o tratamento com o microorganismo. Imagens de MEV revelaram alterações estruturais na parede celular dos resíduos. O pré-tratamento com esta cepa bacteriana tem perspectivas promissoras de melhorar a eficiência do processo de polpação de maneira ambientalmente segura.
Assuntos
Óleo de Palmeira , Enzimas , Lignina , BactériasRESUMO
To assess the outcome of one stage resection and primary anastomosis without intraoperative colonic lavage in patients with acute sigmoid volvulus. A prospective, descriptive study was carried out in the Surgical department of Lady Reading Hospital, Peshawar from Jan 2002 to Dec 2003. Fifty patients with sigmoid volvulus were included in the study. Patients with serious co morbidity, hemodynamic instability, gangrenous or compound volvulus on laparotomy were excluded from the study. All the patients were assessed and operated upon by a senior surgeon. Resection of the sigmoid colon and primary anastomosis was done after only manual decompression in all cases. The demographic data, clinical features, radiologic and operative findings, out come of the procedure in terms of postoperative complications and duration of hospital stay were recorded on a proforma. The data was entered and processed on the SPSS 10 version. The patients included 44 males and 6 females. Male to female ratio was 7.3:1. Mean age was 57 years. Most frequent clinical features were abdominal pain, distension and constipation. Postoperatively, superficial wound infection was seen in 14% patients [n=7], transient paralytic ileus in 22% cases [n=11]. Pulmonary complications occurred in 6% patients [n=3]. No deaths or clinical anastomotic leak occurred. Duration of hospital stay ranged from 6-17days [mean 11 days]. Resection of sigmoid colon primary anastomosis can safely be carried out without on-table colonic lavage in selected patients with viable colon