Giant Catfish Research Articles

Characterization of acid and alkaline proteases from viscera of farmed giant catfish

Abstract This work aimed to characterize acid and alkaline proteases extracted from farmed giant catfish ( Pangasianodon gigas ) viscera by using the aqueous two-phase system (ATPS). Determinations of optimum pH and pH stability, optimum temperature and thermal stability, salt stability and hydrolysis activities against bovine muscle protein and gelatin were performed. ATPS consisting of 20% polyethylene glycol (PEG1500)–15% MgSO 4 or 15% PEG2000–15% NH 3 C 6 H 5 O 7 was used for acid and alkaline proteases extraction. The optimum pH and temperature for acid protease was 3.0 and 40 °C, while alkaline protease was 9.0 and 60 °C. High pH stability of the enzymes was found in the ranges of 1.0–5.0 and 8.0–12.0 for acid and alkaline proteases, respectively. About 40 and 60% activities reduction of acid and alkaline proteases were observed when incubated at 90 °C for 30 min. In addition, 0.5% NaCl addition decreased >50% of total enzyme activities. Hydrolytic activities of the acid and alkaline proteases against bovine muscle protein and gelatin were in the concentration dependent manner as clearly indicated by SDS-PAGE. The results showed that the acid and alkaline proteases obtained from farmed giant catfish viscera could be useful for food protein hydrolysate production.

Three new records of copepods (Siphonostomatoida) parasitic on marine fishes of Iraq, including the relegation of two species of Lernanthropinus to Lernanthropinus temminckii (von Nordmann, 1864)

Three parasitic copepods (Siphonostomatoida) belonging to three different genera were recovered from marine fishes of Iraq, and are listed here as new records. The sea lice Caligus epinepheli Yamaguti, 1936 (Caligidae) was collected from the Japanese threadfin bream, Nemipterus japonicus (Bloch). It had been frequently reported from teleost fishes around the world. The second record, comprising male and female, was another caligid, rarely caught from fishes - Hermilius longicornis Bassett-Smith, 1898, collected from the giant catfish, Netuma thalassina (Rüppell). This paper features the first description of the male of the latter species. The third record was the lernanthropid, Lernanthropinus temminckii (von Nordmann, 1864) (Lernanthropidae), redescribed based on the specimens collected from the greater lizard fish, Saurida tumbil (Bloch) (Synodontidae). In order to clarify its taxonomic status, our specimen was compared with the holotype of L. gibbosus (Pillai, 1964) from the collections of Zoological Survey of India, Kolkata, and the syntypes of L. sauridae Do in Ho and Do, 1985 and L. temminckii from the collections of the Smithsonian Institution, Washington D.C. We found similarities in the morphology of the body, mouthparts, and legs 1-4 in three above-mentioned species. The prominent feature, the setation pattern of legs 1 and 2 was similar in all the female specimens examined. In the light of this, we formally relegate L. gibbosus and L. sauridae to synonymy with L. temminckii. Another important similarity is that Lernanthropinus gibbosus, L. sauridae, and L. temminckii have exclusively been parasitic on lizardfishes (Synodontidae). The attachment site of all three copepods reported form Iraq were the gill filaments.

Breadwaste as a Dietary Supplement for Maize in the Practical Diets of African Giant Catfish (Clarias Gariepinus, Burchell 1822) Fingerlings.

Breadwaste as a Dietary Supplement for Maize in the Practical Diets of African Giant Catfish (Clarias Gariepinus, Burchell 1822) Fingerlings.

Annual Growth and Reproductive Performance in an F2 Catfish Hybrid

Association among growth performance, sex hormone levels, and gonad histology of fifty-four one year old hybrid F2 (Pangasianodon gigas x P. hypophthalmus) were mekong giant catfish and striped catfish hybrids, observations were made during the following periods pre- spawning (March), spawning (June), and post-spawning (October). The overall weight gains of female (174.5±41.3 to 431.8±41.3 g) and male fish (170.0±51.7 to 537.1±51.7 g) were similar. The, average daily gain (ADG of males collected in October (3.24±0.3 g/day) was higher than in June and March. Similarly, the specific growth rate (SGR) of female (0.18±0.02) and male fish (0.25±0.03) were higher in October than in June and March. The highest testosterone values in male fish were observed in June. Gonad histology revealed that spermatozoa were always present in the testes. However, no mature ovaries were observed. More collecting data are needed for further study. However, initiation phase showed that the results indicate that male hybrids mature more quickly than female hybrids the first two years of life. This study showed there was potential for future selective breeding programs with mekong giant catfish and striped catfish hybrids. 

Impacts of Brazil's Madeira River Dams: Unlearned lessons for hydroelectric development in Amazonia

The Santo Antonio and Jirau dams, under construction on the Madeira River, will have significant impacts, including flooding in Bolivia due to the Jirau reservoir's backwater stretch. The reservoirs eliminate natural ecosystems, and the dams block fish migration affecting both biodiversity and commercial production, especially of the giant catfish of the Madeira River that are important resources in Bolivia and Peru as well as Brazil. Changes in flooding regimes in downstream varzea (floodplain) lakes will also affect fisheries. Mercury methylation and greenhouse-gas emissions are additional problems. The reservoirs form part of a planned series of waterways that, if completed, would open large areas in Bolivian Amazonia to soybeans, thus stimulating deforestation. The dams have significant social impacts, including displacing riverside population and eliminating livelihoods from fishing. Despite the technical staff responsible for environmental licensing having submitted a formal opinion considering these concerns to be exceedingly serious and insufficiently studied to authorize dam construction, political appointees approved the licenses. The Madeira Dams offer important lessons for environmental control in Brazil and in many other countries facing similar challenges.

Enhanced recovery of alkaline protease from fish viscera by phase partitioning and its application

BackgroundToo many different protein and enzyme purification techniques have been reported, especially, chromatographic techniques. Apart from low recovery, these multi-step methods are complicated, time consuming, high operating cost. So, alternative beneficially methods are still required. Since, the outstanding advantages of aqueous two phase system (ATPS) such as simple, low cost, high recovery and scalable, ATPS have been used to purify various enzymes. To improve purification efficiency, parameters affected to enzyme recovery or purity was investigated. The objectives of the present study were to optimize of alkaline protease recovery from giant catfish fish viscera by using ATPS and to study of hydrolytic patterns against gelatin.ResultsUsing 70% (w/w) crude enzyme extract (CE) in system (15% PEG2000-15% sodium citrate) provided the highest recovery, PF and KE. At unmodified pH (8.5) gave the best recovery and PF with compare to other pHs of the system. The addition of 1% (w/w) NaCl showed the recovery (64.18%), 3.33-fold and 15.09 of KE compared to the system without NaCl. After addition of 10% (w/w) sodium citrate in the second ATPS cycle, the highest protease recovery (365.53%) and PF (11.60-fold) were obtained. Thus, the top phase from the system was subjected to further studied. The protein bands with molecular weights (MWs) of 20, 24, 27, 36, 94 and 130 kDa appeared on the protein stained gel and also exhibited clear zone on casein-substrate gel electrophoresis. The β, α1, α2 of skin gelatin extensively degraded into small molecules when treated with 10 units of the extracted alkaline protease compared to those of the level of 0.21 units of Flavourzyme.ConclusionsRepetitive ATPS is the alternative strategy to increase both recovery and purity of the alkaline protease from farmed giant catfish viscera. Extracted alkaline protease exposed very high effectiveness in gelatin hydrolysis. It is suggested that the alkaline protease from this fish viscera can further be used in protein hydrolysate production.

The effects of replacement of fish-meal with crab-meal on growth and feed utilization of African giant catfish Heterobranchus longifilis fingerlings

A feeding experiment was conducted in plastic aquaria (46 ´ 38 ´ 28 cm3) to investigate the effect of replacing fish-meal (FM) with crab-meal (CM) on growth, feed utilization and body composition of Heterobranchus longifilis fingerlings with body weight, 3.11 ± 0.56 - 8.48 ± 1.70 g and total length, 73.07 ± 4.99 - 98.69 ± 7.64 mm. Fish and crab-meal were separately used to produce feeds containing 30, 35 and 40% crude protein (CP) and fed to fish for 10 weeks at 5% body weight. The results show that fish fed with 40% CP fish-meal diet had the best growth as indicated in mean weight gain, 6.99 ± 1.70 g; specific growth rate, 4.05 ± 0.19% day-1; feed conversion ratio, 1.12 ± 0.06 and protein efficiency ratio of 2.28 ± 0.12. Diets with FM performed better than CM diets. Percentage survival rate for FM and CM containing diets varied between 91.0 ± 1.63 and 100% and the condition of fish was not significantly different (P > 0.05). Apart from whole body levels of CP in FM fed fish, moisture and fat contents were unaffected by dietary treatments. Deficiency in some essential amino acids and higher dietary ash levels in CM probably impaired effective utilization of these diets compared to FM. Crab-meal diets show appreciable performance and could have potential use as a partial replacer of FM at a particular level. Key words: Heterobranchus longifilis, fish-meal, replacement crab-meal, growth, food utilization.

Histological Alterations in Organs of African Giant Catfish (Heterobranchus bidorsalis) Fingerlings Exposed to Copper Sulphate

Static bioassay was conducted to determine the 96h median lethal level (LC50) of copper sulphate on Heterobranchus biborsalis fingerlings (5.84 ± 0.5 g and length of 6.00 ± 1.0 cm respectively) and to describe the histological changes in the gill, liver, kidney, intestine and heart. LC50 of H. bidorsalis fingerlings was determined graphically as 0.39 ppt. Fish displayed the following behaviors jumping out of the tank (at higher concentration), erratic swimming, discoloration, hyperventilation, irregular operculum and tail beat frequencies and loss reflex during 96 h exposure. Histological examination revealed that gill architecture was destroyed and erosion of gill lamellae, raker and edema. The liver showed distorted liver cells, severe vacuolation of the hepatocytes, fibrosis, coagulative necrosis in the liver parenchyma and round cell infiltration, in the hepatic parenchyma. The kidney showed enlarged globular lumen and damage of proximal tubules, vacuolization and lesions at the highest concentration of copper sulphate. Also the intestine revealed severe degeneration and necrotic changes in the intestinal mucosa cells and submucosa. Lastly the heart showed degeneration of cardiac muscle fiber, atrophy of the cardiac muscle fiber and edema of the atro-ventricular funnel near the entrance of the ventricle on exposure to high concentrations of copper sulphate.

Trace Metals in Muscle, Liver and Gill Tissues of Marine Fishes from Mersing, Eastern Coast of Peninsular Malaysia: Concentration and Assessment of Human Health Risk

Trace metals (Cu, Zn, Cd and Pb) concentrations in muscles, livers and gills of three important marine fishes, Torpedo Scad (Megalaspis cordyla), Sea Catfish (Arius thalassinus) and Belangeri Croaker (Johnius belangeri) were studied using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The samples were collected from Mersing the eastern coastal waters of Peninsular Malaysia. The estimated ranges of Cu, Zn, Cd and Pb concentrations in the muscles, livers and gills of the three fish species were 1.51-3.48, 17.54-28.34, 0.02-0.12 and 0.12-0.15; 15.8-26.0, 80.58-365.1, 2.32-6.14 and 0.57-1.54; 3.04-5.51, 61.63-259.3, 0.03-0.12 and 0.14-2.03 μg g-1 dry weight, respectively. Metal concentrations in the edible parts of the fish were assessed for human consumption according to the Provisional Tolerable Weekly Intake (PTWI) and Provisional Tolerable Daily Intake (PTDI). Generally, levels of metal in muscles were lower than those in livers and gills. Zinc concentration was found to be the highest among the tested metals in all three species. The estimated weekly and daily intakes for the studied metals were far below the PTWI and PTDI limits. Present study reveals that consumption of these fishes from the study area does not pose a risk to human health.

Preparation and functional characterisation of fish skin gelatin and comparison with commercial gelatin

SummaryGelatin was extracted from the skin of farmed giant catfish (GC) and tilapia (TP) at a yield of 19.50% and 23.34% (wet wt). It was high in protein (84–88%) but low in fat (0.09–1.24%) and ash content (0.15–0.17%). The GC exhibited lower emulsifying activity (24–35%), but greater foam ability (98–110%), water holding capacity (477–844%) and fat binding capacity (2541–3314%) than commercial beef skin gelatin (BF) (P < 0.05). GC and TP showed comparable functional properties to BF. SDS‐PAGE patterns of TP gelatin showed high band intensity for the α‐ and β‐components, while the lowest band intensity of the major component was found in the BF. From the study, it can be concluded that the farmed freshwater fish skin GC and TP is a prospective source for producing a significant gelatin yield with desirable functionalities. Because of these, fish skin gelatin could be more effectively and widely used in food industries as a good food ingredient.

Studi Komposisi Isi Lambung Dan Kondisi Morfometri Untuk Mengetahui Kebiasaan Makan Ikan Manyung (Arius thalassinus) Yang Diperoleh Di Wilayah Semarang

Manyung fish (Arius thalassinus) is one of the bottom fish (demersal), which has significant economic potential. One of the measures that can be done to preserve the habitat of fish manyung is a rational exploitation. Information on the biological aspects can be provide additional information on the food and feeding habits and the condition of fish manyung morphometry, to gain a better understanding on the survival and growth of fish. The study was conducted to examine the contents of the stomach and the type of food eaten and the condition of morphometry of manyung fish were caught from the waters around Semarang, manyung fish samples obtained from collectors of Semarang in the krobokan. Manyung fish samples taken on July, August, September and October 2011, with total sample of 50 fish. Retrieval of data in this study conducted in the field and in the laboratory by measuring the weight, total length of fish, fish food organisms manyung frequency, and calculate the volume food organisms of fish manyung. Manyung major food fish (Arius thalassinus) by his preponderance index is a kind of fish with a value of 28.7%. Base of composition of stomach contents, types of mouth (sub terminal), the presence of tentacle, and the length of intestines (1,7-2 times length of the body ) can be concluded manyung fish (Arius thalassinus) is omnivores which tend to be carnivores. The results of 50 samples Manyung fish (Arius thalassinus) gained the most long range artifacts in the interval 55-61 cm (23 fish), weight range for most numerous in the interval 1.6 to 2.7 kg (30 fish).

Heavy Metal Concentration in Fishes from the Coastal Waters of Kapar and Mersing, Malaysia

Although fish is a significant source of protein, they are currently affected by rapid industrialization and mechanized agricultural activities, resulting in increased concentrations of heavy metals in fishes. Concentrations of heavy metals, namely, Cd, Cu, Mn, and Zn, were estimated in the muscle, liver, and gills of two commercially important marine fishes, namely, Arius thalassinus and Johnius belangeri. The fish samples were collected from Kapar and Mersing, which are the west and east coastal waters of Peninsular Malaysia, respectively. The results showed that the muscle had the lowest metal concentrations compared with the liver and gills. Among the estimated heavy metal concentrations, those of Zn and Cd were the highest and the lowest, respectively, for both species in muscle, liver and gills. Moreover, our results indicate that A. thalassinus has higher metal concentrations than J. belangeri in both areas. None of the values in the muscles exceeded the standard guideline values and hence would not pose any health hazard to consumers.

Biochemical and microstructural characteristics of meat samples treated with different plant proteases

This study was conducted to compare the efficiency of different plant proteases for changing biochemical and microstructural characteristics in muscle foods. The meat samples from chicken, giant catfish, pork and beef were treated with four types of proteolytic enzymes: Calotropis procera latex proteases, papaya latex proteases, commercial papain and bromelain at the concentrations of 2 × 10 3 to 6 × 10 3 activity units/100 g of muscle. The pH, collagen solubility, trichloroacetic acid (TCA) soluble peptides, protein patterns and muscle microstructures of the treated samples were evaluated after 24 h at 4°C. A decrease of muscle pH in chicken, giant catfish and pork was observed when the enzymes were added (p < 0.05). A significant increase in collagen solubility was also found in all of the muscle samples (chicken increased from 37.64 to 83.59%; giant catfish increased from 52.82 to 84.14%; pork increased from 14.34 to 86.78; and beef increased from 26.02 to 86.18%; p < 0.05). An increase in TCA-soluble peptides (from 0.90 to18.53 μmole/g sample), and myofibrillar protein degradation was observed in all of the enzyme treated samples as compared to the control (p < 0.05). The electrophoretic pattern of the muscle proteins also revealed extensive proteolysis and reduction of protein bands in all of the treated samples. At the microstructural level, tissue fibers were broken, and the connections between the sarcolemma and the myofibrils were loosened when each enzyme was applied. When comparing all proteolytic enzymes used, papaya latex proteases showed the highest hydrolysis activity in all muscle types, which was followed by C. procera latex proteases, commercial papain, and then bromelain. The results show that these proteolytic enzymes could be used as an effective meat tenderizer. Key words: Proteases, muscle foods, collagen, tenderization, toughness.

Recovery of proteases from the viscera of farmed giant catfish (Pangasianodon gigas) by three-phase partitioning

Three-phase partitioning (TPP) was used to recover proteases from the viscera of farmed giant catfish. Different ratios of crude enzyme extract to t-butanol (1.0:0.5, 1.0:1.0, 1.0:1.5, and 1.0:2.0; v/v) and concentrations of ammonium sulfate ((NH4)2SO4) (20, 30, 40, and 50%; w/v) were investigated. The best protease yield (163%) with a 5-fold purification was obtained in the interphase (I-ph) of the 2nd TPP system, which consisted of the crude extract to t-butanol ratio of 1.0:0.5 in the presence of 50% (NH4)2SO4. A higher concentration of (NH4)2SO4 increased the protease recovery at the interphase, whereas an increase in the t-butanol volume decreased the recovery. SDS-PAGE and zymography revealed a substantial level of isolation of proteases from the viscera of farmed giant catfish by TPP. The molecular weight of the major protease recovered was approximately 25kDa, corresponding to trypsin. The present study demonstrates desirable outcomes and could be used as a primary purification process.

Diversity and Distribution of Fishes in Tropical Estuary Kuantan, Pahang, Malaysia

A study on diversity and distribution of fish communities and water qualities were carried out from January 2009 to December 2010 to cover monsoon and non-monsoon at Kuantan estuary, Pahang, Malaysia. A total of 19 species of primary marine fish belong to 12 families were recorded. Out of 311 individuals the fish fauna was dominated by Ariidae followed by Lutjanidae and Lactaridae. As such Ariidae contributes 50% of the fish caught in the study area and its diversity index (H') was 0.97. A The Ariidae family consist of four (4) species; Arius maculatus, Arius sumatranus, Arius tenuispinis and Arius thalassinus. The Ariidae family can be found in all stations as they are euryhaline (highly tolerant to salinity) and this fish family are known to be a hardy estuarine catfish. Among all species in family Ariidae, Arius thalassinus was the most dominant (23%) among all species. As such collected species showed highest species diversity (0.34) followed by Arius tenuispinis (0.25) compared to other species. Arius tenuispinis alone contributed 11.90% among the samples caught from all stations. The fishes were caught and recorded highest in September-December. Pseudorhombus quinque ocellatus, Nibea soldado, Sardinella fimbriata, Toxotes jaculatrix, Dasyatis ushiei, Setipinna taty were the least dominant in the Kuantan estuary with 9.33% of total abundance. Physico-temperatures, such as temperature (22.03-30 degrees C), Conductivity (10.342.43 mS cm(-1)), TDS (0.06-26.34 mg L(-1)), salinity (0.05-29.09 ppt), DO (6.37-8.38 mg L(-1)), pH (4.97-8.03), Chl a (0.01-1.33 microg L(-1)), nitrite (0.01-0.08 mg L(-1)), nitrate (0.60-0.88 mg L(-1)), phosphate (0.24-0.40 mg L(-1)). Nevertheless, the study envisages that the water quality and fish diversity are still conducive in the Kuantan estuary. The fish diversity of Pahang estuary was high monsoon compared to non-monsoons. The station 4 (LKIM fishing boat jetty and adjacent Hospital Kuantan) is the most polluted area due to the presence of several outskirts could be alarming for the sustainable development of fish and other aquatic organisms in Kuantan estuary in the long run.

The Development Opportunity of Catch Fishery in The Province of Southern Sumatera

South Sumatera province since 2000, began managing the fishery resources separately with the Province of Bangka Belitung. Bangka Belitung contribution in the fisheries sector of the South Sumatera province in 1999 by 72 %. Based on these conditions, then do research on fisheries development opportunities in the surrounding waters of South Sumatera. This research was conducted in February 2006 until July 2006 in two Regency namely Komiring Ogan Ilir and Banyuasin Regency. The results showed that the leading commodities in the province of South Sumatera is shrimp, crab, marine catfish (Arius thalassinus), and wolf herring (Chirosentrus dorab). This leading commodities still have a great opportunity to be developed for their utilization rates still ranged between 58,42% – 66,77% Fishing gear priority based on the analysis of MCA (multy Critical Analysis) with considering the biological aspects, technical, social and economic is trammelnet, drift gillnet and Stationary-bamboo lift net. Key Words: Development, Capture Fisheries , South Sumatera province

Natural outbreak of Streptococcus agalactiae (GBS) infection in wild giant Queensland grouper, Epinephelus lanceolatus (Bloch), and other wild fish in northern Queensland, Australia

Ninety-three giant Queensland grouper, Epinephelus lanceolatus (Bloch), were found dead in Queensland, Australia, from 2007 to 2011. Most dead fish occurred in northern Queensland, with a peak of mortalities in Cairns in June 2008. In 2009, sick wild fish including giant sea catfish, Arius thalassinus (Rüppell), and javelin grunter, Pomadasys kaakan (Cuvier), also occurred in Cairns. In 2009 and 2010, two disease epizootics involving wild stingrays occurred at Sea World marine aquarium. Necropsy, histopathology, bacteriology and PCR determined that the cause of deaths of 12 giant Queensland grouper, three wild fish, six estuary rays, Dasyatis fluviorum (Ogilby), one mangrove whipray, Himantura granulata (Macleay), and one eastern shovelnose ray, Aptychotrema rostrata (Shaw), was Streptococcus agalactiae septicaemia. Biochemical testing of 34 S.agalactiae isolates from giant Queensland grouper, wild fish and stingrays showed all had identical biochemical profiles. The 16S rRNA gene sequences of isolates confirmed all isolates were S.agalactiae; genotyping of selected S.agalactiae isolates showed the isolates from giant Queensland grouper were serotype Ib, whereas isolates from wild fish and stingrays closely resembled serotype II. This is the first report of S.agalactiae from wild giant Queensland grouper and other wild tropical fish and stingray species in Queensland, Australia.

Fish diversity and habitat relationship with environmental variables at Meghna river estuary, Bangladesh

Meghna river estuary is the largest estuarine ecosystem of Bangladesh and support diverse fisheries communities compared to others. Present study was carried out to assess the fish diversity status with relation to major hydrological and meteorological parameters in both spatio-temporal scales. Fish samples were collected together with water quality parameters from eight sampling stations of the Meghna river estuary from November 2011 to April 2012. Fifty years meteorological data were collected from meteorological department. Diversity status were analyzed from all fisheries data by using PAST (version 2.15) software. Findings showed that Meghna river estuary is the habitat of 53 fish species and Oxyurichthys microlepis , Hemiarius sona Arius thalassinus , Batrachocephalus mino and Arius caelatus are the major contributory species (>6%) for both spatio-temporal scales. Water temperature and rainfall was found as major influential factors for species distribution.

Seasonal Feeding Rhythm Associated with Fasting Period ofPangasianodon gigas: Long-Term Monitoring in an Aquarium

The Mekong giant catfish Pangasianodon gigas is endemic to the Mekong River basin, and is recognized as endangered species, largely due to overfishing and development of the river basin. We monitored food intake of P. gigas in a stable environment in an aquarium over a 6-year period and analyzed their feeding rhythm and fasting periods. The daily food intake for each fish was recorded from 18 June 2004 to 17 June 2010. The feeding rhythm or pattern was determined by the fast Fourier transform (FFT) analysis. The FFT analysis revealed that different cycles of feeding rhythm (168.8, 313.1, and 365.3 days) in three catfishes and no observable cycles in two catfishes. However, three catfishes showed subordinate peaks with approximately 365 days (365.3 days for all). These suggest that, at least, four of five catfish had have approximately 365-days feeding cycle. We also showed that all catfish undergo long-term fasting periods (> 20 days). Of note, the feeding/fasting pattern coincides with the wet/dry seasons in Thailand, which also corresponds to the abundance of the catfish food resource (Cladophora spp.). We found that P. gigas exhibit a seasonal feeding rhythm that is synchronized by food availability. Furthermore, we found that the seasonal feeding rhythm was gradually dampened over time, suggesting that the observed seasonal feeding rhythm with long-term fasting of the catfish is likely controlled by an endogenous clock system. To our knowledge, this is the first case of quantification of the seasonal feeding rhythm with fasting periods in teleost fish.

Two phase partitioning and collagen hydrolysis of bromelain from pineapple peel Nang Lae cultivar

Extraction of bromelain from pineapple peel ( Nang Lae cultv.) using aqueous two phase system (ATPS) was optimized. Some biochemical properties including collagen hydrolysis were also investigated. Bromelain predominantly partitioned to the polyethylene glycol (PEG)-rich phase. The highest enzyme activity recovery (113.54%) and purification fold (2.23) were presented in the top phase of 15% PEG2000–14% MgSO 4. Protein pattern and activity staining showed the molecular weight (MW) of bromelain to be about 29 kDa. The extracted bromelain showed the highest relative activity at pH 7.0 and 55 °C. Its activity was decreased continuously by increasing NaCl concentration (up to 1.5% (w/v)). The bromelain extract was applied to hydrolyze the skin collagen of beef and giant catfish (0–0.3 units). The β, α 1, α 2 of giant catfish skin collagen extensively degraded into small peptides when treated with 0.02 units of the bromelain extract. Bovine collagen was hydrolyzed using higher bromelain up to 0.18 units. This study showed the ATPS can be employed to partially purify bromelain from Nang Lae pineapple peel and the enzyme effectively hydrolyzed the collagens.